(PICTURE)(PICTURE) (PICTURE)Europäis hes Patentamt
(1 9) (PICTURE) European Patent Offi_e
(PICTURE) Offi_e euroPéen des brevets (1 1 ) E _ O 644 483 B_
(1 2) EUROPEAN PATENT _PECl FICATlON
(45) Date of pUbliCation and mention (51 ) _nt C_.6_. _O6F 9J46, _O6F 3/O23
of the grant of the patent_.
2O.O1 .1999 Bulletin 1999lO3
(21 ) Application number_. 93114714.4
(PICTURE)(22) Date of filing_. 14.O9.1993
(54) Computer system and method for performing multiple tasks
Rechnersystem und Verfahren zur Ausführung von mehreren Aufgaben
(PICTURE)(PICTURE)
Système d'ordinateur et procédé pour exécuter des tâches multiples
__
_oo
_
_
_ N w. h. . h f h b_. . f h . f h f h E .
_ Ote'_ It In nIne mOnt S rOm t e PU ICatIOn O t e mentIOn O t e 9rant O t e UrOPean Patent_ anY PerSOn maY 9IVe
o nOtiCe tO the EUrOpean Patent OffiCe Of OppOSitiOn tO the EUrOpean patent granted. NOtiCe Of OppOSitiOn Shall be filed in
ii a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art.
w (PICTURE)99(1 ) European Patent Convention). Printed by Jouve, 75OO1 PARIS (FR)
1 EP O 644 483 B1 2
Des_ription on request, to an end user. A virtual machine processes
tasks for the assigned end user by time sharing the host
The invention relates to a computer system for per- processor hardware of the host system. Some host sys-
forming multiple tasks comprising at least one terminal, tems may include more than one hardware processor
at least one application program and a communication 5 so that true simultaneous processing occurs at the host
subsystem. Furtherthe invention relates to a method for since a plurality of processors are running in parallel.
performing multiple tasks in a computer system. More often, there is merely one hardware processorthat
The prior art discloses a variety of inter-program ''concurrently'' runs data processing tasks for the virtual
communication methods in data processing networks machines by a time sharing technique. This is transpar-
comprising a host system connected to a plurality of ter- 1O ent to the end users at the terminals.
minals_. The IBM System Journal, Vol. 22, No. 4, 1 983 Two general types of terminals are employed in da-
discloses a computer network with a communication ta processing networks. The first is referred to as a
subsystem which is the l BM system network architec- ''dumb terminal'' in that it comprises merely a keyboard
ture (SNA). On page 345 of that publication a network and a display device and little or no processing capabil-
is defined as ''a configuration of terminals, controllers, 15 ity other than that required to make a connection with
and processors and the links that connect them''. When the host system. The second type of terminal is referred
such a configuration supports user applications involv- to as an intelligent work station (IWS) and is provided
ing data processing and information exchange and con- with its own processor unit and supporting peripheral
forms to the specifications of the system network archi- devices. The terms IWS and personal computer (PC)
tecture it is called an SNA network. Essentially SNA de- 2O are often used interchangeably. With the ready availa-
fines logical entities that are related to the physical en- bility of PCs having vey attractive price performance
tities in a networkand specifies the rules for interactions characteristics, most new networks are implemented
among these logical entities. The logical entities of an with IWS-type terminals and many of the older networks
SNA network include network addressable units and the are being modified with the replacement of dumb termi-
path control network that connects them. Network ad- 25 nals with lWS-type terminals.
dressable units communicate with one another using Providing each end user on the network with its own
Iogical connections called ''sessions''. The three types processing capability relieves the host CPU from doing
of network addressable units (NAUs) are the logical unit many of the data processing tasks that were previously
(LU), the physical unit (PU), and the system services done at the host. The nature of the tasks that are proc-
control point (SSCP) which are defined as follows_. 3O essed bythe host CPU therefore has changed and more
Logical unit (LU). An LU is a port through which end sophisticated applications such as electronic mail and
users may access the SNA network. An end user uses electronic calendaring are now implemented on the net-
an LU to communicate with another end user and to re- work under the control of the host system. Both of these
quest services of a system services control point (SS- applications involve what is referred to as distributed ap-
CP). 35 plication programs, in that one part of the application
Physical unit (PU). A PU is a component that man- program is resident on the host system and another is
ages the resources of a node in corporation with an SS- resident on the IWS terminal.
CP. Many of the current data processing networks are
System services control point (SSCP). This is a fo- designed in accordance with the IBM SNA architecture
cal point for configuration management, problem deter- 4O which was first described in 1 974. Since then various
mination and directory services for end users. SSCPs new functions and services have been added. As sug-
may have sessions with LUs and PUs. When such a gested earlier, SNA networks can be viewed as a plu-
session occurs, the LU or PU is in the domain of the rality of nodes interconnected by data links. At each of
SSCP. In addition to sessions with LUs and PUs, SSCPs these nodes, path control elements send information
mayalso communicate with each othertocoordinate the 45 packets, referred to as path information units (PIUs) be-
initiation and the termination of sessions between logi- tween resource managers called logical units. These
cal units and in different domains. Iogical connections of the paths are called a session. A
From the hardware standpoint a simple network transport network for data is therefore defined by the
comprises a host system having a processing unit and path control elements and the data link control ele-
a plurality of remote terminals that are assigned to indi- 5O ments.
vidual users. The remote terminals are selectively con- Nodes can be connected by a plurality of links and
nectable to the host system through one or more com- comprise a plurality of LUs. Various types of LUs ses-
munication links. These links may comprise a coaxial sions and protocols have been established within the
cable, a dedicated telephone line or, in some cases, a frameworkofthe SNAarchitecture. There are three gen-
satellite communication link. 55 eral classes of sessions. The first class is unspecified
The host processing unit must always have an op- by SNA. The second class involves terminals and the
erating system which supports the creation of a large third involves program to program communication. For
number of virtual machines each of which is assigned, example, LU 6 provides SNA defined inter-program
2
3 EP O 644 483 B1 4
COmmUniCatiOn prOtOCOlS WhiCh aVOidS the limitatiOnS Of tWeen the appliCatiOnS prOgram A_ and the terminal T.
terminal LU types such as LU 2 and LU 7. LU 6.2 is re- The communication subsystem 3 may comprise further
ferred to as advanced program to program communica- host computers not shown in the drawing. The logical
tiOn Or APPC prOtOCOlS. COnneCtiOn L betWeen the appliCatiOnS prOgram A_ and
Logical units are more than message ports. LUs 5 the terminal T which is established via the communica-
provide operating system services such as program to tion subsystem 3 is also called a session.
program communication involving one or more local A user of this prior art computer system is confront-
programs. Each application program use the LUs as a ed with a problem of not being able to effectuate inter-
Iocal operating system and the network of loosely cou- rupt driven events at the user's command. For example,
pled LUs connected by sessions as a distributed oper- 1O while a user is using the computer system for creating
ating system. a report using an editor, the user may need to interrupt
The LU allocates a plurality of resources to its pro- the word processing session and switch instantly to an-
grams, which are dependent on the particular hardware other program, such as to look up a phone number that
and its configuration. Some of the resources that are resides in an application program that is different from
made available are remote while others are local, i.e. , 15 the one the user is using as an editor.
associated with the same LU as the application pro- Furthermore, in some cases it is necessay to input
gram. The sessions are considered local resources at a large number of data via the terminal T on request of
eaCh LU, bUt are Shared betWeen partiCUlar LUS. the appliCatiOnS prOgram A_ , SUCh aS addreSSeS Of CUS-
The control function of an LU is resource allocation. tomers. If these data are present as a file stored on a
Programs request access to a resource. Sessions which 2O storage medium of the computer system, it is desirable
Carry meSSageS betWeen LUS Or prOgramS rUnning On that the data be inpUt tO the appliCatiOnS prOgram A_ aU-
LUs are considered to share resources. A session is di- tomatically without interaction of the user. However, in
vided into a plurality of serially executed conversations. general, this is not possible without changing the appli-
TWO LUS COnneCted by a SeSSiOn haVe a Shared re- CatiOnS prOgram A_ WhiCh eXpeCtS the USer tO inpUt the
sponsibility in allocating sessions to application pro- 25 data via the terminal T on its request. ln order to perform
gramS fOr USe aS ''COnVerSatiOnS''. The appliCatiOn prO- the taSk aUtOmatiCally, the appliCatiOnS prOgram A_
grams are therefore sometimes referred to ''transaction would have to be changed so that data can be inputted
programs''. automatically from the file stored in the computer system
The successful connection between LUs occurs as without interaction of the user. In order to automate the
a result of a common set of protocols which function first 3O task the applications program A_ would have to be at
to activate a session between two LUs and second to least partially rewritten which normally involves a major
facilitate the exchange of message data. A request to effort in time and resources. Consequently, in some cas-
activate a session between two logical units is also es, the user has to perform the tedious task of inputting
called ''Bl ND''. the data via the terminal T by hand. This is also disad-
The SNA format and protocol reference manual 35 vantageous since processing time of the computer sys-
designated SC 3O-31 1 2, published by the l BM Corpora- tem and the resources of the communication subsystem
tion, describes SNA by defining, for example, with pro- are wasted as the inputting of the data by hand requires
gramming language declarations, the format of messag- a relatively long period of time as compared with the au-
es that flow between network entities and the programs tomatic data input from the file.
that generate, manipulate, translate, send and return 4O It is therefore an object of the present invention to
messages. provide and improved computer system and an im-
The SNA transaction program reference manual for proved method for performing multiple tasks in a com-
LU 6.2 referred to as GC 3O-3O84, published by the l BM puter system.
Corporation, defines the verbs that describe the func- The object of the present invention is solved by the
tions provided by the implementing products. 45 features laid down in the independent claims. Preferred
Even though SNA type communication subsystems embodiments of the invention are given in the depend-
are widely used other communication subsystems such ent claims.
as the transmission control protocol/internet protocol According to the invention the data stream between
(TCP/l P) which is an UNIX-type/ethernet-based sys- the application program and the terminal is intercepted
tem-interconnect protocol are known from the prior art. 5O and routed to a virtual terminal. This is controlled by a
Fig. 1 shows a prior art example of a computer sys- virtual terminal manager.
tem in which an application program is logically connect- The concept of virtual terminals is known as such,
ed via a communication subsystem to a terminal T. The for example from US-A-5 1 O9 51 O, EP-A-O 1 1 4 357 and
computer system comprises at least a host 2 and a com- Lantz et al, ''Virtual Terminal Management in a Multiple
munication subsystem 3. The applications program A_ 55 Process Environment'', 1 979, Proceedings of the 7th
is stored in storage space 1 of the host 2. The commu- Symposium on Operating System Principles, pp. 86-97.
nication subsystem which is, for example, of an SNA or However, the prior art is silent as to the application of a
TCP/l P type, serves to establish a logical connection be- virtual terminal concept in a computer system compris-
3
5 EP O 644 483 B1 6
ing a number of host computers being interconnected the application program as real terminal. Thereby back-
with one another and with terminals by an SNA, TCP/l P ground operation is made possible.
or similar type of communication subsystem. The invention is advantageous in that it allows mul-
According to the present invention the virtual termi- tiple sessions to share one real terminal device. When
nal manager creates a true in-storage image of the dis- 5 a user switches sessions by using a ''hot key'' function,
play screen by analyzing the received data stream ac- the virtual terminal manager allows the access to the
cording to the actual data stream architecture, such as data of the new virtual terminal for the real device, still
an SNA 327O data stream. The in-storage image con- maintaining all other active virtual terminals in the back-
tains all information about content, layout, color and ground. Further, updates of virtual terminal buffers
highlighting etc. of the real display screen. 1O which are currently not displayed on a real terminal are
The virtual terminal manager also performs all func- made possible as well as the display of partial data of
tions defined by the data communication protocol of the two or more virtual terminal buffers on the real terminal.
communication subsystem. Thus the virtual terminal This allows a user to view more than one host session
simulates the appearance of a real terminal to an appli- on his screen.
cation program. lt is completely transparent to the ap- 15 The vi_ual terminal manager provides an AP inter-
plication program whether it works with a virtual terminal face for each virtual terminal. This allows the writing of
or a real terminal. programs which can modify virtual terminal buffers be-
The virtual terminal manager provides a double in- fore they are displayed on the real terminal. It also may
terface to the communication subsystem in that it is pos- simulate user input providing for an automated opera-
sible for the application program and the real terminal 2O tion. This automated operation may even act on screen
to access the virtual terminal at the same time. The con- content of the dedicated virtual terminal of one applica-
sistency of multiple access operations to the virtual ter- tions program to provide an answer to a request of an-
minal advantageously is controlled and monitored by other applications program.
the virtual terminal manager. In the following a preferred embodiment of the in-
Since the virtual terminal manager receives the da- 25 vention is described in more detail with reference to the
ta stream prior to the real terminal, it can modify the vir- drawing in which
tual terminal buffer before sending the data to the real
terminal. This modification can be_. Fig. 1 is a schematic diagram of a prior art
computer system,
- Conversion to different code standards, e.g. from 3O
EBCDl C to ASCll , Fig. 2, 3, 4 is a schematic diagram of preferred
embodiments of the computer system
- conversion to different transmission protocols, e.g. according to the invention,
from SNA to TCP/l P, 35 Fig. 5 is a schematic diagram showing the
- conversion into another language code page, correlation of multiple sessions,
- improved presentation of old application programs, Fig. 6 is a flow-chart illustrating the establish-
e.g. by adding color etc. , ment of a session,
4O
- usage of an application programming interface Fig. 7 is a schematic diagram showing the us-
(APl) provided by the virtual terminal manager to age of a cross application program ac-
add data to the virtual terminal buffer, cording to the invention.
- data transfer from other virtual terminals to a spe- 45 The inventive computer system shown in Fig. 2 dif-
cific virtual terminal by usage of an APl program, fers from the prior art computer system of Fig. 1 in that
it additionally comprises a virtual terminal 4, a virtual ter-
- overlay of a message window on the user screen. minal manager 5, an application programming interface
6 belonging to the virtual terminal manager 5 and a user
ln an SNA type environment for example the vi_ual 5O simulation program 7. A logical connection L_ is estab-
terminal manager SimUlateS the fUnCtiOnality Of One Or liShed betWeen the appliCatiOnS prOgram A_ and itS ded-
more LUs as required. Thus a logical connection is es- icated virtual terminal 4 via the communication subsys-
tabliShable Via the SNA COmmUniCatiOn SUbSyStem be- tem 3. A lOgiCal COnneCtiOn l_ _ iS eStabliShed betWeen
tween the application program and its dedicated virtual the terminal T and the dedicated virtual terminal 4 of the
terminal. This logical connection in principle is inde- 55 applications program A_ . The data stream coming from
pendent frOm the eXiStenCe Of anOther lOgiCal COnneC- the appliCatiOnS prOgram A_ Via the lOgiCal COnneCtiOn
tiOn betWeen a real terminal and the dediCated VirtUal L_ iS prOCeSSed by the VirtUal terminal fUnCtiOn. The data
terminal since the dedicated virtual terminal appears to is thereby stored as a screen image which is always a
4
7 EP O 644 483 B1 8
true copy of a real screen buffer, including the extended This is according to an algorithm depending on the re-
attribute buffer. In this example, each session is under quirements of the specific application and is implement-
the control of the IBM virtual telecommunications ac- ed in the user simulation program 7.
cess method VTAM preferably featuring IBM's ad- To keep the screen image in a virtual terminal con-
vanced communication functions. The virtual telecom- 5 sistent with the requirements of the application, the user
munications access method (VTAM) is a set of l BM pro- simulation program 7 is not allowed to change the
grams that control communication between terminals screen layout when acting as an operator. The user sim-
and application programs and which cooperates with ulation program 7 can only alter the contents of the vir-
SNA. The virtual terminal manager makes usage of tual terminal buffer when a user would be allowed to en-
VTAM for the establishment of the logical connections. 1O ter data on the real terminal. The virtual terminal man-
If the lOgiCal COnneCtiOn l__ betWeen the terminal T ageraSSUreS the COnSiStenCy by re_eCting inValid aCCeSS
and the virtual terminal 4 is no longer maintained, this requests to the virtual termial buffer via the application
iS nOt tranSparent tO the appliCatiOnS prOgram A_ , SinCe prOgramming interfaCe 6.
the lOgiCal COnneCtiOn L_ iS adapted tO be maintained The COmpUter SyStem Of Fig. 3 additiOnally COmpriS-
independently from the existence of the logical connec- 15 es a further applications program A_ which is stored in
tiOn l__. If the appliCatiOnS prOgram A_ reqUireS inpUt StOrage SpaCe 1 2 in the hOSt 2, a dediCated Vi_Ual ter-
frOm the USer, thiS inpUt OperatiOn iS Carried OUt aUtO- minal 9 Of the appliCatiOnS prOgram A_ and a SWitCh 1 1
matically by the user simulation program 7. The user which is realized by the software of the virtual terminal
simulation program 7 has access to the virtual terminal manager 5 and the application programming interface
4 and in pa_icular to the virtual terminal buffer of the 2O 6. Logical connection C_ is established between vi_ual
virtual terminal 4 which comprises a true in-storage im- terminal 9 and user simulation program 7 which in this
age of the real screen. example is a cross application program 7. The cross ap-
Since the virtual terminal buffer is held preferably in plication program 7 serves to integrate two or more ap-
the main memory of the computer system the user sim- plications programs. This is explained in more detail in
ulation program 7 constantly monitors the contents of 25 the following_.
the Vi_Ual terminal bUffer. The USer SimUlatiOn prOgram A lOgiCal COnneCtiOn L_ iS eStabliShed betWeen the
7 aCCeSSeS the VirtUal terminal bUffer Via the appliCatiOn appliCatiOnS prOgram A_ and the dediCated VirtUal ter-
programming interface 6 of the virtual terminal manager minal 9 via the communication subsystem 3. The logical
5. The appliCatiOn prOgramming interfaCe 6 prOVideS all COnneCtiOn l__ in thiS CaSe iS eStabliShed Via the COm-
necessaryfunctions to access the virtual terminal buffer. 3O munication subsystem 3 and the switch 1 1 . If the posi-
The user written user simulation program 7 gets access tion of switch 11 is changed, another logical connection
tOthe Vi_Ual terminal 4 thrOUgh the appliCatiOn prOgram- l__ iS eStabliShed betWeen the Vi_Ual terminal 9 and the
ming interface 6 provided by the virtual terminal manag- terminal T. The position of the switch 1 1 is changed on
er 5. The application programming interface provides request of the user of the terminal T by issuing a corre-
the following function requests_. 35 sponding command via the logical connection l__ to the
virtual terminal manager.
- Establishment and control of the application and The position of switch 1 1 can also be changed on
terminal SeSSiOnS L_,, l_,_ (in thiS eXample L_ and l__). reqUeSt Of the USer SimUlatiOn prOgram 7 WhiCh in thiS
example is a cross application program.
- Establishment and control of the vi_ual terminals. 4O First the case is considered in which the user is
WOrking With the appliCatiOnS prOgram A_ . TherefOre the
_ If a pIUrality Of VirtUal terminaIS iS eStabliShed by the lOgiCal COnneCtiOnS L_ and l__ are eStabliShed. The ap-
Vi_Ual terminal manager 5'. COntrOl WhiCh Vi_Ual ter- pliCatiOnS prOgram A_ reqUeStSthe inpUt Of CUStOmerda-
minal is displayed on the real terminal T and ex- ta, for example, name, street, city and turnover from the
change of data between the user simulation pro- 45 user. ln order to find out the turnover of a specific cus-
gram and different ones of the virtual terminals. tomer the user must work with a second applications
prOgram A_ in Order tO gain aCCeSS tO a data baSe. ThUS
The function requests are used for the program- the user requests that the position of switch 11 be
ming Of the USer SimUlatiOn prOgram 7 WhiCh may be Changed in Order tO eStabliSh the lOgiCal COnneCtiOn l__.
written in an interpreter language like _EXX or a com- 5O This is done by issuing a corresponding command from
pilable normal language like PU1 or C. The application the terminal T to the virtual terminal manager 5, prefer-
programming interface 6 provides a way to control the ably by making use of a ''hot key''.
aCCeSS Of mUltiple USer SimUlatiOn prOgramS 7 rUnning OnCe the lOgiCal COnneCtiOn l__ iS eStabliShed the
concurrently to the virtual terminals of the virtual termi- user inputsthe name and address of a specific customer
nal manager 5 by maintaining a logical connection be- 55 in order to find out the turnover of that customer by
tWeen a VirtUal terminal - fOr eXample Vi_Ual terminal 4 meanS Of appliCatiOnS prOgram A_. In reSpOnSe tO a USer
and lOgiCal COnneCtiOn C_ - and the USer SimUlatiOn prO- reqUeSt the SWitCh 1 1 iS Shifted baCk intO itS Sta_ing pO-
gram 7 On demand Of the USer SimUlatiOn prOgram 7. SitiOn SO that again the lOgiCal COnneCtiOn l__ iS eStab-
5
9 EP O 644 483 B1 1 O
lished. The user may now input all of the required cus- es an independent virtual terminal 1 4. The independent
tomer data - including the turnover - into applications terminal 1 4 is dedicated to the cross application pro-
prOgram A_ . gram. The independent VirtUal terminal 1 4 iS ObSeNed
If an SNA 327O data Stream iS USed, the data by the USer Of terminal T SinCe a lOgiCal COnneCtiOn C_
streams in the communication subsystem 3 consist of 5 is established via switch 11 and communication subsys-
user-provided data and commands that logical units tem 3 between the independent virtual terminal 1 4 and
transmit over an LU-session. Logical units also transmit terminal T.
COntrOl infOrmatiOn that gOVernS the Way the data iS han- If fOr eXample the appliCatiOnS prOgram A_ reqUireS
dled and formatted. The SNA 327O data stream is the the customer identification number (ID) in order to ac-
only data stream that LU types 2 and 3 use. It is an op- 1O cess customer data, such as turnover, outstanding
tional data stream for LU types 6. 1 and 6.2. The data claims of unpaid bills and the date of the last reminder,
Stream SUppOrtS file-tO-file tranSfer, diSplay appliCatiOnS, the appliCatiOnS prOgram A_ reqUeStS a CUStOmer l D tO
and printer applications. be inputted. This is recognized by the cross application
Generally, an application program communicates program 7 which is connected with the virtual terminal
with a display operator using one of two methods_. 15 4 of applications program A_ , since the cross application
In the first method, the application program leaves the program 7 observes the virtual terminal buffer of the vir-
diSplay SUrfaCe UnfOrmatted, and the OperatOr USeS it in tUal terminal 4. If the appliCatiOnS prOgram A_ reqUireS
a free-form manner. In the second method, the applica- the input of a customer identification number which is
tion program completely or partially formats the display not known to the cross application program, the cross
surface (i.e. organizes or arranges it into fields) and the 2O application program accesses the applications program
OperatOr enterS data intO the fieldS. The SeCOnd methOd A_ by the lOgiCal COnneCtiOn C_. Name and addreSS Of
is used in the example shown in Fig. 3 since the display a specific customer is input into the virtual terminal buff-
operator - especially the user of the terminal T - is only er of the virtual terminal 9, the data base of applications
allOWed tO inpUt data at SpeCified pOSitiOnS in the Vi_Ual prOgram A_ iS qUeried and the reSUlt iS retUrned tO the
terminal buffers of the application programs A_ , A_. 25 virtual terminal buffer of the virtual terminal 9. Then the
The SNA 327O data stream allows the application cross application program 7 inputs the required custom-
programmerto divide the display surface into one active er l D which is found out by means of the applications
area, and, OptiOnally, One Or mOre referenCe areaS. EaCh prOgram A_ intO the VirtUal terminal 4 Of the appliCatiOnS
area iS Called a pa_itiOn. The pa_itiOn that iS ''aCtiVe'' prOgram A_ . The infOrmatiOn prOVided by appliCatiOnS
contains a cursor and is the only partition in which the 3O program A_ is monitored by the cross application pro-
OperatOr Can enter data Or reqUeStS. gram Via the lOgiCal COnneCtiOn C_ . In the eXample
The second case considered here is that of user shown in Fig. 4 the cross application program 7 recog-
simulation program 7 which in this example is a cross nizes that there are outstanding claims. This relevant
application program. If the cross application program 7 information is output via logical connection L, to the in-
is running, the above described procedure of the first 35 dependent virtual terminal 1 4. Thus the user of the com-
case is carried out automatically. If the applications pro- puter system is only notified as to a specific customer if
gram A_ reqUeStS the CUStOmer data and eSpeCially the there are OUtStanding ClaimS Of Unpaid bilIS Of that CUS-
turnover to be inputted, this is recognized by the cross tomer.
appliCatiOn prOgram 7 Via the lOgiCal COnneCtiOn C_ . AS The independent VirtUal terminal 1 4 iS prOVided by
a consequence the cross application program 7 inputs 4O the virtual terminal manager 5. The independent virtual
the name and address of a specific customer via logical terminal 1 4 is not in session with an application program.
COnneCtiOn C_tOthe VirtUal terminal 9 Of the appliCatiOnS ThiS allOWS the Set-Up Of a SCreen layOUt WhiCh iS deter-
prOgram A_ and ObSerVeS the VirtUal terminal bUffer Of mined by the CrOSS appliCatiOn prOgram 7. In thiS CaSe
the virtual terminal 9 for the result of the quey in the the cross application program 7 controls the session to
data base of the applications program A_ which yields 45 the real terminal via logical connection C_. Thereby it is
the required turnover of the customer. This number is possible to define any screen layout to present a new
read from the virtual terminal buffer of applications pro- interface to the user of the terminal T. The screen layout
gram A_ and tranSferred tO the CrOSS appliCatiOn prO- may COmbine the OUtpUtS Of tWO Or mOre appliCatiOn
gram 7 Via the lOgiCal COnneCtiOn C_. The CrOSS appli- SCreenS aS it iS ShOWn in the figUre.
cation program 7 inputs the turnover automatically via 5O ln summary, a user simulation program 7 therefore
IOgiCal COnneCtiOn C_ tO VirtUal terminal 4. On the neXt may perfOrm One Or mOre Of the fOllOWing taSkS'.
reqUeSt Of the appliCatiOnS prOgram A_ the Same Se-
quence of operations is carried out again automatically. - simulation of user input to an application program
This is done without interaction of the user. The user for frequently repeated tasks (cf. the preferred em-
may observe any one of the application programs if a 55 bodiment shown in Fig. 2),
IOgiCal COnneCtiOn l__ Or l__tO One Of the VirtUal terminal
buffers is established via switch 1 1 . - integration of data obtained from virtual terminal
The computer system of Fig. 4 additionally compris- buffers which hold a true in storage screen image
6
1 1 EP O 644 483 B1 1 2
of currently invisible application programs; the data advantageously carried out by making usage of VTAM.
is integrated into the screen of the currently dis- In this case only a pointer to the storage location where
played application program (cf. the preferred em- the virtual terminal buffer of that application program is
bodiment of Fig. 3), stored has to be sent to the real terminal. This also im-
5 proves the operation of the communication subsystem,
- provision of a new user interface to one or more ap- since transmission time is saved. Consequently switch
plication programs by providing a newscreen layout 1 1 can be activated very frequently without blocking the
in an independent virtual terminal (cf. the preferred communication subsystem 3.
embodiment of Fig. 4). Fig. 5 shows a more detailed view of the computer
1O system shown in Fig. 3. The user simulation program 7
This approach is particularly advantageous in that is not shown in Fig. 5. The computer system shown in
it provides application program-to-application program Fig. 5 additionally comprises with respect to the compu-
communication without any change to the effective pro- ter system of Fig. 3 an additional virtual terminal 1 5.
grams. Each of the virtual terminals 4, 9, 1 5 comprises a control
The appearance to the end user of one or more ap- 15 block B1 , B2, BT and a vi_ual terminal buffer VTA1 ,
plication programs can be changed without changing VTA2, VTT1 , respectively. The switch 1 1 is interposed
the application programs themselves. The user simula- between virtual terminals 4, 9 which are dedicated to an
tion program 7 or the cross application program 7 can application program and the virtual terminal 1 5 which is
be written by the user without any impact on the com- dedicated to the real terminal T.
munication subsystem 3 of the computer system. Fur- 2O The virtual terminal 1 5 of the real terminal T is al-
thermore, the programmer of the user simulation pro- ready generated when the computer system is switched
gram 7 orthe cross application program 7 does not have on. Preferably the computer system is controlled by the
to have any knowledge about the nature of the data IBM program Netview Access Services orasimilar prod-
stream. This is because a usersimulation program 7 can uct which manages the establishment of interconnec-
directly access the screen of an application program by 25 tions between the components of the computer system.
access tothe corresponding virtual terminal buffer using First, the selection menu of Netview Access Services is
the APl function requests defined bythe application pro- shown on the real terminal T or in other words the se-
gramming interface 6. Furthermore, this approach is ad- lection menu is stored in the virtual terminal buffer VTT1 .
vantageous since it allows for running the same user This corresponds to step 6O of the flow-chart shown in
simulation program 7 or cross application program 7 3O Fig. 6. In the terminal control block BT resource identi-
concurrently multiple times, each serving a different us- fication table (RIDT) is stored. The Rl DT comprises a
er Of a different terminal T With different VirtUal terminaIS pOinter P_ WhiCh pOintS tO the VirtUal terminal bUffer
involved. VTT1 .
Furthermore, the present invention is particularly Then the user of the real terminal T selects an ap-
beneficial because the communication subsystem 3 is 35 plications program A_, of the application programs
used more efficiently. Whenever a jump, escape or sim- present in the computer system from the selection menu
ilar type of operation requires the saving of a current shown on virtual terminal 1 5 (step 61 ). This request of
screen content only the newly modified data has to be the user to work with the applications program A_, is
added to virtual terminal buffer of the application pro- transferred to applications program A_, (step 62). This
gram which is in session with the terminal T. No full 4O transfer is preferablyaccomplished by means of the l BM
screen read operation must be issued if, for example, program Netview Access Services. The applications
the switch 1 1 is activated in order to change sessions. program A_, tests whether it can fulfil the user request.
This is because virtual terminal buffers always keep a If this is the case an empty control block is selected
true in-storage image of the real screen in the main and marked with an identifier so that this control block
memory of the computer system. Ajump operation from 45 becomes the control block B., of the applications pro-
One appliCatiOn prOgram tO anOther - i.e. Changing the gram A_, (Step 63). Then a lOgiCal COnneCtiOn l_,_ iS eStab-
position of switch 1 1 in Fig. 3 - or an escape operation lished between the dedicated virtual terminal VT_, of the
where no session with the real terminal T is maintained, applications program A_, and the real terminal T by
only necessitates that the newly modified data which putting switch 1 1 into the required position (step 64). In
was modified after the last enter command of the user 5O the example shown in Fig. 5 the applications program
be added tO the VirtUal terminal bUffer Of the appliCatiOn A_ iS SeleCted by the USer and the SWitCh 11 iS pUt intO
prOgram frOm WhiCh the jUmp Or eSCape OperatiOn iS Car- a pOSitiOn SO that the lOgiCal COnneCtiOn l__ iS eStab-
ried out. When the screen of that application program lished. The function of the switch 1 1 is realized by stor-
haS tO be reStOred later On tO the real terminal T, the age Of a firSt pOinter P__ in the COntrOl blOCk B_ . The
correspondingvi_ual terminal being assigned tothat ap- 55 pointer P__ points to the control block BT of the real ter-
pliCatiOn prOgram Will generate a data Stream - SUCh aS minal T. A SeCOnd pOinter P_ iS StOred in the COntrOl
an SNA 327O data Stream - OUt Of itS SaVed VirtUal ter- blOCk BT. The SeCOnd pOinter P_ pOintS tO the COntrOl
minal buffer and send it to the real terminal. This step is block B_, of the applications program A_, which is selected
7
1 3 EP O 644 483 B1 1 4
by the USer. In the eXample ShOWn in Fig. 5 the pOinter P_ Ofthe appliCatiOn prOgramS i are StOred in an Ordered
P_ iS thUS pOinting tO the COntrOl blOCk B_ Of the SeleCted table SO that the COrreSpOnding pOinter P__ WhiCh iS re-
appliCatiOnS prOgram A_ . qUired fOr Changing the pOSitiOn Of SWitCh 1 1 iS Obtained
Each control block B_,, BT - which is not an empty from that table. That table is established under the con-
control block - comprises a resource identification table 5 trol of the virtual terminal manager 5. If there is more
RIDT. Data as to the resources allocated by the LU - than one real terminal T there is a multiplicity of first
WhiCh iS SimUlated by the VirtUal terminal manager 5 - tO pOinterS P_,_ SinCe eaCh terminal T reqUireS a different
the appliCatiOnS prOgram A_, Or the real terminal T iS firSt pOinter P_,_. The firSt pOinterS are aISO StOred in an
stored in the Rl DT of the corresponding control block B_, ordered table. This table is accessed by the virtual ter-
or BT. 1O minal manager 5 in order to read the required first point-
EaCh reSOUrCe identifiCatiOn table in eaCh Of the er P_,_ - in thiS eXample the pOinter P__ - WhiCh pOintS tO
control blocks B_,, BT comprises storage fields to indicate the terminal control block BT of the terminal T from
the aCtUal State Of the VirtUal terminal bUffer VTAi Of the WhiCh the reqUeSt tO aCCeSS appliCatiOnS prOgram A_ iS
VirtUal terminal VTi tO WhiCh the COntrOl blOCk B_, belOngS. iSSUed. The pOinter P__ iS StOred in the COntrOl blOCk B_
These storage fields comprise data as to the screen 15 by the virtual terminal manager 5.
size, the number of rows and columns of the screen, the Thirdly - in the example shown in Fig. 5 - an SNA
cursor position and other hardware characteristics. 327O data stream is generated from the data stored in
These data are inputted into the resource identification the virtual terminal 9. This data stream is transmitted to
tables of the control blocks B_,, BT by a ''BIND'' request the real terminal T which consequently shows the
of the corresponding applications program A., or the vir- 2O screen of the applications program A_.
tual terminal T, respectively. Fig. 7 shows a more detailed view of the computer
The virtual terminal 1 5 of the real terminal T is op- system of Fig. 4. Once the cross application program 7
tional. If no selection menu is used, virtual terminal buff- is started the program establishes logical connections
er VTT1 iS ObSOlete. HOWeVer the COntrOl blOCk BT iS C_ , C_, C_ by meanS Of the appliCatiOn prOgramming in-
still required to store the second pointer P_.,. lf a new 25 terface 6 and the vi_ual terminal manager 5 tothe virtual
IOgiCal COnneCtiOn l_,_ betWeen a VirtUal terminal VT_, Of terminaIS 4, 9, 1 5 and eSpeCially tO the COntrOl blOCkS
one of the application programs i and the real terminal B1 , B2, BT in order to gain access to the corresponding
T is established, the contents of virtual terminal buffer virtual terminal buffers VTA1 , VTA2, VTT1 . Data from
VTT1 is no longer displayed on the real terminal T, but these virtual terminals can be composed by cross appli-
the contents of the virtual terminal buffer VTAi - in the 3O cation program 7 to a new screen which is stored in the
example shown in Fig. 5 the contents of VTA2 - of the independent virtual terminal 1 4 of the cross application
applications program A_, which is newly selected. If the program 7. The screen stored in independent virtual ter-
user requests anotherapplication program -for example minal 1 4 can be transmitted by issuing an appropriate
the appliCatiOnS prOgram A_ - the pOSitiOn Of the SWitCh appliCatiOn prOgramming interfaCe COmmand frOm the
1 1 is changed correspondingly as indicated by the 35 cross application program 7 via the logical connection
daShed lineS in Fig. 5. Thereby the lOgiCal COnneCtiOn C_ tO the VirtUal terminal 1 5 fOr diSplay On the real ter-
l__ iS eStabliShed. minal T. The iSSUing Of the COmmand iS indiCated by the
The case that the user requires a change from the dotted line in Fig. 7.
preSently SeleCted appliCatiOnS prOgram A_ tO the appli- The preferred embOdiment Of FigS. 4 and 7 iS par-
cations program A_ is considered by way of example. 4O ticularly beneficial forthe integration of applications pro-
The following sequence is carried out_. grams. If a plurality of applications programs is given -
FirStly real terminal T ShOWS the SCreen Of the ap- SUCh aS appliCatiOnS prOgramS A_ and A_ - theSe are
pliCatiOnS prOgram A_ Or in Other WOrdS the Vi_Ual ter- COmbined by the CrOSS appliCatiOn prOgram 7 in the fOl-
minal 4 Of that appliCatiOnS prOgram A_ iS diSplayed On lOWing Way'.
the real terminal T. Then the user presses a ''jump'' key 45
in order to indicate the request to change from applica- a) One applications program A_, of the plurality of ap-
tiOnS prOgram A_ tO appliCatiOnS prOgram A_. The preSS- pliCatiOnS prOgramS iS SeleCted, i.e. a lOgiCal COn-
ing ofthe ''jump'' key implies that the newly modified data nection C_, to the corresponding virtual terminal VT_,
stored in the data buffer of the real terminal T are stored of that applications program A_, is established. Fur-
in the virtual terminal buffer VTA1 so that the vi_ual ter- 5O ther, the cross application program 7 obseNes the
minal 4 hods the latest update of the screen contents of virtual terminal VT_,. This is done by obseNation of
the real terminal T befOre the appliCatiOnS prOgram A_ the VirtUal terminal bUffer VTAi Of the VirtUal terminal
is left. buffer VT_,. The cross application program 7 ob-
SeCOndlythe firSt pOinter P__ iS Changed tO be a nUll SeNeS the VirtUal terminal bUffer VTAi by making US-
pointer in order to indicate that the logical connection l__ 55 age of the function requests provided by the appli-
iS nO lOnger eStabliShed. The SeCOnd pOinter P_ iS CatiOn prOgramming inte_aCe.
Changed SO that it pOintS tO the COntrOl blOCk B_ Of the
neWly SeleCted appliCatiOnS prOgram A_. The pOinterS b) If the appliCatiOnS prOgram A_, reqUeStS the inpUt
8
1 5 EP O 644 483 B1 1 6
of information, this is recognized by the cross appli- i) The switch 1 1 is put into a position so that a logical
CatiOn prOgram 7 dUe tO itS ObSeNatiOn Of the VirtUal COnneCtiOn C_ iS eStabliShed betWeen the inde-
terminal VT_,. In response to this request of informa- pendent virtual terminal VT, 1 4 and the terminal T.
tion by the applications program A_, the cross appli- The user is thereby notified of the response of the
cation program 7 selects another applications pro- 5 applications program A_, since the independent vir-
gram A__ which can provide for the requested infor- tual terminal VT, 1 4 is displayed on the terminal T.
mation. Preferably a look-up table is stored in the computer
c) Consequently, a logical connection C__ to the cor- system for the selection in the above step b). This look-
responding virtual terminal VT__ of that applications 1O up table assigns a requested information to a specific
program A__ is established. applications program which can provide for the request-
ed information. Therefore each table entry is a pair of a
d) The applications program A__ is requested by the requested information and the corresponding program
cross application program 7 to provide for the infor- which can provide for the requested information. In the
mation which is requested by the applications pro- 15 above described step b) this table is accessed in order
gram A_, (cf. step b). This is done by inputting a cor- to find and select the applications program A__ which can
responding query request via the logical connection provide for the information requested by the applications
C__ to the virtual terminal VT__ of the applications pro- program A_,.
gram A__. 2O
e) The cross application program 7 observes the vir- Claims
tual terminal VT__ by observation of the virtual termi-
nal buffer VTAj. Once the requested information is 1 . Computer system for performing multiple tasks,
present in the virtual terminal VT__, this information said computer system comprising at least one ter-
is outputted via the logical connection C__ tothe cross 25 minal T, a communication subsystem (3), a plurality
application program 7. Again the cross application of host computers and a plurality of applications
program 7 accesses the virtual terminal - in this programs which are stored on different ones of said
case VT__ - by the function requests provided by the host computers, each of said applications programs
application programming interface 6. The request- A_, having a dedicated virtual terminal VT_, (4, 9) as-
ed information is inputted via the logical connection 3O signed thereto,
C_, into the virtual terminal VT_, of the applications wherein
program A_,. a logical connection L_, is establishable via said
f) The cross application program 7 obseNes the vir- communication subsystem between one of
tual terminal VT_, of the applications program A_, for 35 said applications programs A_, and its dedicated
the response of the applications program A_, to the virtual terminal VT_, (4, 9),
input of the requested information. said logical connection L_, is adapted to be main-
g) Once the response of the applications program tained independently from the existence of a
A_, to the input of the requested information is 4O logical connection l_,_ between said terminal T
present, this response is outputted via the logical and said dedicated virtual terminal VT_,, and
connection C_, to the cross application program by
means of the application programming interface 6. said logical connections are establishable by
The response of the applications program A_, is test- means of a virtual telecommunications access
ed whether it fulfills a predefined criterium. ln the 45 method.
example of Fig. 4 the predefined criterium is wheth-
er there are outstanding claims or not. 2. Computer system according to claim 1 , wherein
h) If the predefined criterium is fulfilled by the re- said dedicated virtual terminal VT_, (4) having a
sponse, a logical connection L, is established be- 5O dedicated control block B., assigned thereto,
tween the cross application program 7 and its inde-
pendent virtual terminal VT, 1 4. The response of said terminal T having a dedicated terminal
the application program A_, is inputted into the inde- control block BT assigned thereto, and
pendent virtual terminal VT, 1 4 via the logical con-
nection L,. Additional textural information can be 55 said logical connection l.,_ between said termi-
added in order to explain the response to the user nal T and said dedicated virtual terminal VT_, is
(Cf. the teXtUral infOrmatiOn in the independent Vir- eStabliShable by StOrage Of a firSt pOinter P_,_ in
tual terminal 1 4 shown in Fig. 4). said control block B_, and storage of a second
9
1 7 EP O 644 483 B1 1 8
pOinter P_ in Said terminal COntrOl blOCk BT, pliCatiOn prOgramS StOred On different OneS Of Said
Said firSt pOinter P_,_ pOinting tO Said terminal hOSt COmpUterS and a COmmUniCatiOn SUbSyStem
COntrOl blOCk BT and Said SeCOnd pOinter P_ (3), Said methOd COmpriSing the fOllOWing StepS in
pointing to said control block B_,. which the logical connections are established by
5 means of a vi_ual telecommunication access
3. Computer system according claim 2, wherein said mode _.
firSt pOinter P_,_ being a nUll pOinter if Said lOgiCal
COnneCtiOn l_,_ betWeen Said terminal T and Said a) SeleCting an appliCatiOnS prOgram A_, OUt Of
dedicated virtual terminal VT_, is not established. said plurality of application programs,
1O
4. Computer system according to claim 2 or 3, wherein b) establishing a logical connection L_, via said
a dediCated VirtUal terminal VT_ iS aSSigned tO Said COmmUniCatiOn SUbSyStem betWeen Said appli-
terminal T and said terminal control block BT pref- cations program A_, and a dedicated virtual ter-
erably COmpriSeS a Vi_Ual terminal pOinter P_ WhiCh minal VT_, (4, 9),
points to said dedicated virtual terminal VT_ of said 15
terminal T. C) eStabliShing a lOgiCal COnneCtiOn l_,_ betWeen
said terminal T and said dedicated virtual ter-
5. Computer system according to any one of the pre- minal VT_,,
ceding claims, wherein said computer system fur-
ther comprises a user simulation program (7) and a 2O d) maintaining said logical connection L_, inde-
dedicated virtual terminal VT, (1 4) which is as- pendently from the existence of said logical
Signed tO Said USer SimUlatiOn prOgram, COnneCtiOn l_,_.
a lOgiCal COnneCtiOn C_, (C_ , C_) betWeen Said 9_ MethOd aCCOrding tO Claim 8, Wherein Said lOgiCal
user simulation program and said dedicated vir- 25 connection L., is established by
tual terminal VT_, of said application program is
eStabliShable Under tO the COntrOl Of Said USer a) aSSigning a dediCated COntrOl blOCk B_, (B_ ,
SimUlatiOn prOgram, and B_) tO Said dediCated Vi_Ual terminal VT_,,
a logical connection C_ between said terminal 3O b) assigning a dedicated terminal control block
T and said dedicated virtual terminal VT, is es- BT to said terminal T,
tablishable C) StOring a firSt pOinter P_,_ in Said COntrOl blOCk
6. Computer system according to claim 5, wherein B_,,
said logical connection C_, between said user simu- 35
IatiOn prOgram and Said dediCated VirtUal terminal d) StOring a SeCOnd pOinter P_ in Said terminal
VT_, of said applications program A_, is establishable control block BT,
by storage of a third pointer P_,, in said control block
B_, and StOrage Of a fOUrth pOinter P,_, in a StOrage Whereby Said firSt pOinter P_,_ pOintS tO Said terminal
Iocation which is assigned to said user simulation 4O control block BT and said second pointer P__, points
program, said third pointer P_,, pointing to said user to said control block B_,.
simulation program and said fourth pointer P,_, point-
ing to said program specific control block B_,. 1 O. Method according to claim 8 or 9, said computer
system further comprising a user simulation pro-
7. Computer system according to claim 5 or 6, wherein 45 gram (7) and a dedicated virtual terminal VT, (1 4)
Said lOgiCal COnneCtiOn C_ betWeen Said terminal T WhiCh iS aSSigned tO Said USer SimUlatiOn prOgram,
and said dedicated virtual terminal VT, of said user said method comprising the following steps_.
simulation program is establishable by storage of a
fifth pOinter P__ in Said terminal COntrOl blOCk BT a) SeleCting an appliCatiOnS prOgram A__ OUt Of
and by storage of a sixth pointer P__ in a storage 5O said plurality of application programs,
Iocation assigned to said user simulation program,
Said fifth pOinter P__ pOinting tO Said USer SimUlatiOn b) SeleCtiVely eStabliShing One Or mOre lOgiCal
prOgram and Said SiXth pOinter P__ pOinting tO Said COnneCtiOnS C_,, C__ betWeen Said USer SimUla-
terminal specific control block BT. tion program and said dedicated virtual termi-
55 nals VT.,, VT_. of said applications programs A.,,
8. Method for performing multiple tasks in a computer A__,
system, said computer system comprising a termi-
nal T, a plurality of host computers, a plurality of ap- c) selectively establishing a logical connection
1 O
1 9 EP O 644 483 B1 2O
C_ betWeen Said terminal T and Said dediCated kann, WObei der erSte Zeiger P_,_ aUf den Da-
virtual terminal VT, of said user simulation pro- tenstationssteuerblock BT verweist und der
gram. ZWeite Zeiger P_ aUf den SteUerblOCk B_, Ver-
weist.
1 1 . Computer system or method according to any one 5
of the preceding claims, wherein said dedicated vir- 3. Rechnersystem nach Anspruch 2, wobei der erste
tUal terminal COmpriSeS a VirtUal terminal bUffer Zeiger P_,_ ein NUll Zeiger iSt, Wenn die LOgikVerbin-
(VTA1 , VTA2, VTT1 ) WhiCh iS StOred in a main mem- dUng l_,_ ZWiSChen der DatenStatiOn T Und der dedi-
ory of said computer system independently from the zierten virtuellen Datenstation VT_, nicht hergestellt
existence of a logical connection between said ter- 1O wurde.
minal T or
- if present - said user simulation program and said 4. Rechnersystem nach Anspruch 2 oder 3, wobei ei-
dediCated Vi_Ual terminal. ne dediZierte VirtUelle DatenStatiOn VT_ der Daten-
station T zugewiesen wird und wobei der Datensta-
15 tionssteuerblock BT vorzugsweise einen vi_uellen
PatefttaftSFtfü_he DatenStatiOnSZeiger P_ Umfaßt, der aUf die dedi-
Zierte Vi_Uelle DatenStatiOn VT_ der DatenStatiOn T
1 . Rechnersystem für die Ausführung mehrerer Auf- verweist.
gaben, wobei das Rechnersystem mindestens eine
Datenstation T, ein Kommunikationsteilsystem (3), 2O 5. Rechnersystem nach einem beliebigen der voran-
eine Vielzahl von Hostrechnern und eine Vielzahl gegangenen Ansprüche, wobei das Rechnersy-
von Anwendungsprogrammen umfaßt, die auf ver- stem weiter ein Benutzersimulationsprogramm (7)
schiedenen der Hostrechner gespeichert sind, wo- und eine dedizierte virtuelle Datenstation VT, (1 4)
bei jedes der Anwendungsprogramme A_, über eine umfaßt, die dem Benutzersimulationsprogramm zu-
dedizierte virtuelle Datenstation VT_, (4, 9) verfügt, 25 gewiesen ist,
die ihr zugewiesen ist,
WObei eine LOgikVerbindUng C_, (C_ , C_) ZWiSChen
dem Benutzersimulationsprogramm und der
eine Logikverbindung L_, über das Kommunika- dedizierten virtuellen Datenstation VT_, des An-
tionsteilsystem zwischen einem der Anwen- 3O wendungsprogramms unter der Steuerung
dungsprogramme A_, und seiner dedizierten vir- durch das Benutzersimulationsprogramm her-
tuellen Datenstation VT_, (4, 9) hergestellt wird, gestellt werden kann, und
die LOgikVerbindUng L_, geeignet iSt, Unabhän- eine LOgikVerbindUng C_ ZWiSChen der Daten-
gig vom Vorhandensein einer Logikverbindung 35 station T und der dedizierten virtuellen Daten-
l_,_ ZWiSChen der DatenStatiOn T Und der dedi- StatiOn VT, hergeStellt Werden kann.
zierten virtuellen Datenstation VT_, aufrechter-
halten zu werden, und 6. Rechnersystem nach Anspruch 5, wobei die Logik-
verbindung C_, zwischen dem Benutzersimulations-
die Logikverbindungen mit einem Verfahren für 4O programm und der dedizierten virtuellen Datensta-
den virtuellen Telekommunikationszugang her- tion VT_, des Anwendungsprogramms A_, durch die
gestellt werden können. Speicherung eines dritten Zeigers P_,, in dem Steu-
erblock B_, und die Speicherung eines vierten Zeiger
2. Rechnersystem nach Anspruch 1 , wobei P,_, in einem Speicherbereich hergestellt werden
45 kann, der dem Benutzersimulationsprogramm zu-
die dedizierte virtuelle Datenstation VT_, (4) gewiesen ist, wobei der dritte Zeiger P_,, auf das Be-
über einen dedizierten Steuerblock B_, verfügt, nutzersimulationsprogramm verweist und dervierte
der ihr zugewiesen ist, Zeiger P,_, auf den programmspezifischen Steuer-
block B_, verweist.
die Datenstation T über einen dedizierten Steu- 5O
erblock BT verfügt, der ihr zugewiesen ist, und 7. Rechnersystem nach Anspruch 5 oder 6, wobei die
LOgikVerbindUng C_ ZWiSChen der DatenStatiOn T
die LOgikVerbindUng l_,_ ZWiSChen der DatenSta- Und der dediZierten VirtUellen DatenStatiOn VT, deS
tion T und der dedizierten virtuellen Datensta- Benutzersimulationsprogramms durch die Spei-
tion VT., durch die Speicherung eines ersten 55 cherung eines fünften Zeigers P__ in dem Daten-
ZeigerS P_,_ in dem SteUerblOCk B_, Und die Spei- StatiOnSSteUerblOCk BT Und dUrCh die SpeiCherUng
CherUng eineS ZWeiten ZeigerS P_ in dem Da- eineS SeChSten ZeigerS P__ in einem SpeiCherbe-
tenstationssteuerblock BT hergestellt werden reich hergestellt werden kann, der dem Benutzersi-
21 EP O 644 483 B1 22
mulationsbereich zugewiesen ist, wobei der fünfte a) Auswählen eines Anwendungsprogramms
Zeiger P__ aUf daS BenUtZerSimUlatiOnSprOgramm A__ aUS der VieIZahl VOn AnWendUngSprOgram-
VerWeiSt Und der SeChSte Zeiger P__ aUf den daten- men,
stationsspezifischen Steuerblock BT verweist. 5 b) selektives Herstellen einer oder mehrerer
8. Verfahren für die Ausführung mehrerer Aufgaben in Logikverbindung C_,, C__ zwischen dem Benut-
einem Rechnersystem, das eine Datenstation T, ei- zersimulationsprogramm und den dedizierten
ne Vielzahl von Hostrechnern, eine Vielzahl von An- virtuellen Datenstationen VT_,, VT__ der Anwen-
wendungsprogrammen, die auf verschiedenen der dungsprogramme A_,, A__,
Hostrechner gespeichert sind, und ein Kommunika- 1O
tionsteilsystem (3) umfaßt, wobei das Verfahren, in c) selektives Herstellen einer Logikverbindung
dem die LOgikVerbindUngen mit einem V__ahren C_ ZWiSChen der DatenStatiOn T Und der dedi-
für den virtuellen Telekommunikationszugang her- zierten virtuellen Datenstation VT, des Benut-
gestellt werden, die folgenden Schritte umfaßt_. zersimulationsprogramms.
15
a) Auswählen eines Anwendungsprogramms 1 1 . Rechnersystem oder Verfahren nach einem belie-
A_, aus der Vielzahl der Anwendungsprogram- bigen der vorangegangenen Ansprüche, wobei die
me, dedizierte virtuelle Datenstation einen virtuellen
Datenstationspuffer (VTA1 , VTA2, VTT1 ) umfaßt,
b) Herstellen einer Logikverbindung L_, über das 2O der im Hauptspeicher des Rechnersystems gespei-
Kommunikationsteilsystem zwischen dem An- chert ist, unabhängig vom Vorhandensein einer Lo-
wendungsprogramm A_, und einer dedizierten gikverbindung zwischen der Datenstation T oder -
virtuellen Datenstation VT_, (4, 9), falls vorhanden - dem Benutzersimulationspro-
gramme und der dedizierten virtuellen Datenstati-
c) Herstellen einer Logikverbindung l_,_ zwi- 25 on.
schen der Datenstation T und der dedizierten
virtuellen Datenstation VT_,, Revendi_ations
d) Aufrechterhalten der Logikverbindung L_, un-
abhängig vom Vorhandensein der Logikverbin- 3O 1 . Système informatique destiné à exécuter des tâ-
dUng l_,_. CheS mUltipleS, ledit SySteme infOrmatiqUe COmpre-
nant au moins un terminal T, un sous-système de
9. Verfahren nach Anspruch 8, wobei die Logikverbin- communications (3), une pluralité d'ordinateurs hô-
dung L_, hergestellt wird durch tes et une pluralité de programmes d'applications
35 qui sont mémorisés sur des ordinateurs différents
a) Zuweisen eines dedizierten Steuerblocks B_, parmi lesdits ordinateurs hôtes, chacun desdits pro-
(B_ , B_) ZU der dediZierten Vi_Uellen DatenSta- grammeS d'appliCatiOnS A_, ayant Un terminal Vi_Uel
tion VT_,, réservé VT_, (4, 9) qui lui est affecté,
dans lequel
b) Zuweisen eines dedizierten Datenstations- 4O
steuerblocks BT zu der Datenstation T, une connexion logique L_, peut être établie par
l'intermédiaire dudit sous-système de commu-
C) SpeiChern eineS erSten ZeigerS P_,_ in dem niCatiOnS entre l'Un deSditS prOgrammeS d'ap-
Steuerblock B_,, plications A_, et son terminal virtuel réservé VT_,
45 (4, 9),
d) SpeiChern eineS ZWeiten ZeigerS P_ in dem
Datenstationssteuerblock BT, ladite connexion logique L_, est conçue pour être
maintenue indépendamment de l'existence
WObei der erSte Zeiger P_,_ aUf den DatenStatiOnS- d'Une COnneXiOn lOgiqUe l_,_ entre ledit terminal
steuerblock BT und der zweite Zeiger P_., auf den 5O T et ledit terminal virtuel rése_é VT.,, et
Steuerblock B_, verweist. Iesdites connexions logiques peuvent être éta-
1 O. Verfahren nach Anspruch 8 oder 9, wobei das blies au moyen d'un procédé d'accès de télé-
Rechnersystem weiter ein Benutzersimulationspro- communications virtuelles.
gramm (7) und eine dedizierte virtuelle Datenstati- 55
on VT, (1 4) umfaßt, die dem Benutzersimulations- 2. Système informatique selon la revendication 1 ,
programm zugewiesen ist, wobei das Verfahren die dans lequel
folgenden Schritte umfaßt_. 1 2
23 EP O 644 483 B1 24
Iedit terminal virtuel réservé VT_, (4) comporte de simulation d'utilisateur et ledit quatrième poin-
un bloc de commande réservé B_, qui lui est af- teur P,_, pointant sur ledit bloc de commande spéci-
fecté, fique du programme B_,.
Iedit terminal T comporte un bloc de commande 5 7. Système informatique selon la revendication 5 ou
de terminal reSerVe BT qUi IUi eSt affeCte, et 6, danS leqUel ladite COnneXiOn lOgiqUe C_ entre le-
dit terminal T et ledit terminal virtuel réservé VT, du-
Iadite COnneXiOn lOgiqUe L_,_ entre ledit terminal dit prOgramme de SimUlatiOn d'UtiliSateUr peUt etre
T et ledit terminal virtuel réservé VT_, peut être établie par la mémorisation d'un cinquième pointeur
établie par la mémorisation d'un premier poin- 1O P__ dans ledit bloc de commande de terminal BT
teUr P_,_ danS ledit blOC de COmmande B_, et la et par la memOriSatiOn d'Un SiXieme pOinteUr P__
memOriSatiOn d'Un SeCOnd pOinteUr P_ danS le- danS Un emplaCement de memOriSatiOn affeCte
dit bloc de commande de terminal BT, ledit pre- audit programme de simulation d'utilisateur, ledit
mier pOinteUr P_,_ pOintant SUr ledit blOC de COm- CinqUieme pOinteUr P__ pOintant SUr ledit prOgram-
mande de terminal BT et ledit second pointeur 15 me de simulation d'utilisateur et ledit sixième poin-
P_,_ pOintant SUr ledit blOC de COmmande B_,. teUr P__ pOintant SUr ledit blOC de COmmande Spe-
cifique du terminal BT.
3. Système informatique selon la revendication 2,
danS leqUel ledit premier pOinteUr P_,_ eSt Un pOin- 8. PrOCede deStine à eXeCUter deS tâCheS mUltipleS
teur null si ladite connexion logique l.,_ entre ledit 2O dans un système informatique, ledit système infor-
terminal T et ledit terminal Vi_Uel reSerVe V_ n'eSt matiqUe COmprenant Un terminal T, Une pIUralite
pas établie. d'ordinateurs hôtes, une pluralité de programmes
d'applications mémorisés sur des ordinateurs diffé-
4. Système informatique selon la revendication 2 ou rents parmi lesdits ordinateurs hôtes, et un sous-
3, dans lequel un terminal virtuel réservé VT_ est 25 système de communications (3), ledit procédé com-
affecté audit terminal T et ledit bloc de commande prenant les étapes suivantes dans lesquelles les
de terminal BT comprend de préférence un pointeur connexions logiques sont établies au moyen d'un
de terminal VirtUel P_ qUi pOinte SUr ledit terminal mOde d'aCCeS de teleCOmmUniCatiOnS VirtUelleS '.
Vi_Uel reSerVe VT_ dUdit terminal T. 3O a) sélectionner un programme d'application A_,
5. Système informatique selon l'une quelconque des parmi ladite pluralité de programmes d'applica-
revendications précédentes, dans lequel ledit sys- tions,
tème informatique comprend en outre un program-
me de simulation d'utilisateur (7) et un terminal vir- b) établir une connexion logique L_, par l'inter-
tuel réservé VT, (1 4) qui est affecté audit program- 35 médiaire dudit sous-système de communica-
me de simulation d'utilisateur, tions entre lesdits programmes d'applications
A_, et un terminal virtuel réservé VT_, (4, 9),
Une COnneXiOn lOgiqUe C_, (C_ , C_) entre ledit
prOgramme de SimUlatiOn d'UtiliSateUr et ledit C) etablir Une COnneXiOn lOgiqUe l_,_ entre ledit
terminal virtuel réservé VT_, dudit programme 4O terminal T et ledit terminal virtuel réservé VT_,,
d'application peut être établie sous la comman-
de dudit programme de simulation d'utilisateur, d) maintenir ladite connexion logique L_, indé-
et pendamment de l'existence de ladite con-
neXiOn lOgiqUe l_,_.
une connexion logique CT entre ledit terminal 45
T et ledit terminal virtuel réservé VT, peut être 9. Procédé selon la revendication 8, dans lequel ladite
établie. connexion logique L_, est établie
6. Système informatique selon la revendication 5, a) en affectant un bloc de commande réservé
dans lequel ladite connexion logique C_, entre ledit 5O B_, (B_ , B_) audit terminal virtuel réservé VT_,,
programme de simulation d'utilisateur et ledit termi-
nal virtuel réservé VT_, dudit programme d'applica- b) en affectant un bloc de commande de termi-
tions A_, peut être établie par la mémorisation d'un nal réservé BT audit terminal T,
troisième pointeur P_,, dans ledit bloc de commande
B_, et la mémorisation d'un quatrième pointeur P,_, à 55 c) en mémorisant un premier pointeur P_,_ dans
un emplacement de mémorisation qui est affecté ledit bloc de commande B_,,
audit programme de simulation d'utilisateur, ledit
trOiSieme pOinteUr P_,, pOintant SUr ledit prOgramme d) en memOriSant Un SeCOnd pOinteUr P_ danS
1 3
25 EP O 644 483 B1 26
Iedit bloc de commande de terminal BT,
d'Où il reSUlte qUe ledit premier pOinteUr P_,_ pOinte
sur ledit bloc de commande de terminal BT et ledit
second pointeur P__, pointe sur ledit bloc de com- 5
mande B_,.
1 O. Procédé selon la revendication 8 ou 9, ledit système
informatique comprenant en outre un programme
de simulation d'utilisateur (7) et un terminal virtuel 1O
réservé VT, (1 4) qui est affecté audit programme
de simulation d'utilisateur, ledit procédé compre-
nant les étapes suivantes _.
a) sélectionner un programme d'applications A__ 15
parmi ladite pluralité des programmes d'appli-
cations,
b) établir sélectivement une ou plusieurs con-
nexions logiques C_,, C__ entre ledit programme
de simulation d'utilisateur et lesdits terminaux 2O
virtuels réservés VT_, , VT__ desdits programmes
d'applications A_,, A__,
c) établir sélectivement une connexion logique
C_ entre ledit terminal T et ledit terminal VirtUel
réservé VT, dudit programme de simulation 25
d'utilisateur.
1 1 . Système ou procédé informatique selon l'une quel-
conque des revendications précédentes, dans le-
quel ledit terminal virtuel réservé comprend un tam- 3O
pon de terminal virtuel (VTA1 , VTA2, VTT1 ) qui est
mémorisé dans une mémoire principale dudit sys-
tème d'ordinateur indépendamment de l'existence
d'une connexion logique entre ledit terminal T ou
- s'il est présent - ledit programme de simulation 35
d'utilisateur et ledit terminal virtuel réservé. 4O
45
5O
55
1 4
(PICTURE)
EP O 644 483 B1
15
_ (PICTURE)
EP O 644 483 B1
16
(PICTURE)
EP O 644 483 B1
17
(PICTURE)
EP O 644 483 B1
18
(PICTURE)
EP O 644 483 B1
19
(PICTURE)
EPO644483 B1
FIG. 6
(PICTURE)
EP O 644 483 B1
21