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The IBM 1130 Computing System was introduced in 1965. It was IBM's least-expensive computer to date, and was aimed at price-sensitive, computing-intensive technical markets like education and engineering. The IBM 1800 was a process control variant of the 1130 with two extra instructions (CMP and DCM) and extra I/O capabilities.
Description
The 1130 became quite popular, and the 1130 and its non-IBM clones gave many people their first feel of "personal computing." Though its price-performance ratio was good and it notably included inexpensive disk storage, it otherwise broke no new ground technically. The 1130 holds a place in computing history primarily because of the fondness its former users hold for it.
The IBM 1130 used System/360 electronics packaging called Solid Logic Technology (SLT) and had a 16-bit binary architecture, not very different from later minicomputers like the PDP-11 or Data General Nova. The address space was 15 bits, limiting the 1130 to 32K 16-bit words of core memory. Both direct and indirect addressing capabilities were implemented. Amazing loops were possible.
Much programming was done in Fortran. The 1130 Fortran compiler could run on a machine with only 4K words of core. That's 8 kilobytes, the minimum file allocation on many PC's. To maximize speed and conserve space, the operating system and compilers were written entirely in assembly language, and employed techniques seen less frequently today including tight integration of code and data as well as self-modifying code.
Other programming languages available on the 1130 included: APL, BASIC, COBOL, FORTH, PL/I and RPG. Eastern Michigan University developed a Fortran IV compiler for the 1130. The basic 1130 came with an IBM 2310 disk drive. These read pizza-box-sized 2315 single platter cartridges that held 512 K words or 1 M byte (less than a 3.5" floppy). Disk memory was used to store the operating system, object code, and data, but not source code. The last was kept on punch cards. The disk operating system was called DMS or DM2 (for Disk Monitor System, Release 2).
Other available peripherals included the IBM 1132 and IBM 1403 lineprinters, the IBM 1442 card reader/punch, the IBM 2311 Disk Drive, the IBM 2250 Graphic Display Unit and the IBM 1627 drum plotter. The plotter was very useful for engineering work. The console typewriter used an IBM Selectric mechanism, which meant one could change the type by replacing a hollow, golf-ball sized type element. There was a special type element available for APL, a powerful array-oriented programming language using a special symbolic notation.
The IBM 1130 MTCA, for Multiple Terminal Control Adapter, was announced late in the 1130's product life; it allowed up to four 2741 terminals to be connected to an IBM 1130, for use with APL.
A standard 1130 had a 3.6 microsecond memory cycle time, with a more expensive model equipped with 2.2 µs memory cycle time. (You could use the latter with a 1403 printer connected through a 1133 multiplexer.) To further tap the low end of the market, IBM introduced the 1130 Model 4, with a 5.6 µs cycle time - at a lower price of course. The Model 4's 1132 printer was derated as well, but the slower CPU still could not keep up with it. (The 1132 used the CPU to determine when to fire the print wheels as they rotated, a very compute intensive function.) Careful readers of the 1130 hardware manual discovered that when the printer interrupt level (4) was on, the 1130 Model 4 ran at the faster 3.6 us cycle time. Some users of the Model 4 would write a phony printer driver that turned on level 4 and left it on. They would call this driver when running a compute intensive job and write their output to disk, the printer being unusable, of course. When done, they'd run a normal program to print their output.
IBM 1130 Models
IBM implemented five models of the 1131 Central Processing Unit which was the primary processing component of the IBM 1130 Computing Systems.
Storage Speed
|
|||||
Storage Size |
3.6-microsec. storage cycle |
3.6-microsec. storage cycle plus disks |
3.6-microsec. storage cycle (70% performance) single disk |
2.2-microsec. storage cycle plus disks |
2.2-microsec. storage cycle (no internal disk) |
| 4096 words | Model 1A |
Model 2A |
Model 4A |
--- |
--- |
| 8192 words | Model 1B |
Model 2B |
Model 4B |
Model 3B |
Model 5B |
| 16,384 words | Model 1C |
Model 2C |
--- |
Model 3C |
Model 5C |
| 32,768 words | Model 1D |
Model 2D |
--- |
Model 3D |
Model 5D |
The IBM 1800 was a variant of the IBM 1130 with additional features for process control applications. Just as the IBM 1130 was a successor to the IBM 1620, the IBM 1800 was a sucessor to the IBM 1710
Chronology
- Feb. 11, 1965 - IBM introduces the 1130 (Models A1, A2, B1 and B2). Also announced is the IBM 1132 printer, the lowest cost online computer printer ever announced by IBM at that time.
- Fourth Quarter 1965 - First customer shipments begin from the San Jose plant.
- August 9, 1966 - IBM rolls out the 1130 synchronous communications adapter, which permits the small 1130 system to be connected by regular leased telephone lines to, and function as a communications terminal for, any model of the IBM System/360.
- April 17, 1967 - A four-way expansion of the 1130 is announced (Models B3, C2, C3, D2 and D3), involving:
- five times the disk storage and four times the magnetic core memory size;
- an additional processing speed almost 40 percent faster than previously available;
- More and faster peripheral equipment, including an optical mark reader;
- an improved commercial programing package.
- January 1968 - First shipments begin of the 1130 Models B3, C2, C3, D2 and D3.
- July 1968 - The Boca Raton plant begins shipping the 1130.
- July 22, 1971 - 1130 Models 4A and 4B are introduced at new levels of economy.
- September 1971 - First customer shipments begin of the 1130 Model 4.
- May 31, 1972 - Models 1C, 1D, 5B, 5C and 5D are announced.
Trivia
Brian Utley was the 1130's Project Manager during its development and introduction. Brian said at the third 11/30 party that before IBM Marketing named the 1130 it was known as the Small Engineering Computer System or SECS. The initial architecture was 18 bits but was changed to 16 bits due to the influence of the System/360 development. The full dialogue of his 2005 presentation is available here.
Notable software designer Grady Booch got his first exposure to programming on an IBM 1130. Quote from interview:
... I pounded the doors at the local IBM sales office until a salesman took pity on me. After we chatted for a while, he handed me a Fortran *. I'm sure he gave it to me thinking, "I'll never hear from this kid again." I returned the following week saying, "This is really cool. I've read the whole thing and have written a small program. Where can I find a computer?" The fellow, to my delight, found me programming time on an IBM 1130 on weekends and late-evening hours. That was my first programming experience, and I must thank that anonymous IBM salesman for launching my career. Thank you, IBM.
Also Guy Steele wrote a LISP interpreter for the IBM 1130 when he was in high school (Boston Latin School, which had an IBM 1130 for student use) (Personal recollection)
Chuck Moore wanted to call his new language "Fourth" but the IBM 1130 operating system was limited to five character names, so it wound up being called FORTH.
Dan Bricklin creator of the VisiCalc program got his start in programming when he learned and used the IBM 1130 as part of the National Science Foundation Computer/Math Summer Project for high school students, given at the University of Pennsylvania in 1966.
An IBM 1130 with 8 kilowords of core was used for the world's first full-time Search for Extraterrestrial Intelligence research at The Ohio State University Radio Observatory.
Instruction set overview
Main Registers: IAR = Instruction Address Register ACC = Accumulator EXT = Extension Register XRx = Index Registers x = 1,2,31130 Instruction Set Mnemonics: LD = Load ACC STO = Store ACC LDD = Load Double (ACC & EXT) STD = Store Double (ACC & EXT) LDX = Load Index STX = Store Index LDS = Load Status STS = Store Status A = Add ACC AD = Add Double S = Subtract ACC SD = Subtract Double M = Multiply D = Divide AND = Boolean And OR = Boolean Or XOR = Boolean Exclusive Or SLA = Shift Left ACC SLT = Shift Left ACC & EXT SLCA = Shift Left and Count ACC SLC = Shift Left and Count ACC & EXT SRA = Shift Right ACC SRT = Shift Right ACC & EXT RTE = Rotate Right ACC & EXT XCH = Exchange ACC and EXT MDM = Modify Memory B = Branch BSC = Branch or Skip on Condition (Modifier dependant) i.e. BP BNP BN BNN BZ BNZ BC BO BOD BSI = Branch and Store IAR MDX = Modify Index and Skip WAIT = Halt NOP = No Operation XIO = Execute I/O
1800 Additional Instruction Mnemonics: CMP = Compare ACC DCM = Double Compare ACC & EXT
Short instruction format (one 16 bit word): 1 Bits 0...45678......5 OP---FTTDisp
OP is Operation F is format 0 = Short TT is Tag Disp is Displacement
Long instruction format (two 16 bit words): 1 1 Bits 0...456789.....50..............5 OP---FTTIMod
Address
-OP is Operation F is format 1 = Long TT is Tag I is Indirect bit Mod is Modifier
Effective Address Calulation (EA): F = 0 | F = 1, I = 0 | F = 1, I = 1 Direct Addressing| Direct Addressing| Indirect Addressing
--- TT = 00 | EA = Displ + IAR | EA = Add | EA = C/Add TT = 01 | EA = Displ + XR1 | EA = Add + XR1 | EA = C/Add + XR1 TT = 10 | EA = Displ + XR2 | EA = Add + XR2 | EA = C/Add + XR2 TT = 11 | EA = Displ + XR3 | EA = Add + XR2 | EA = C/Add + XR3
--- Disp = Contents of displacement field Add = Contents of address field of instruction C = Contents of location specified by Add or Add + XR
Programming Examples
The examples can be executed on the IBM 1130 emulator available at IBM 1130.org.
Snoopy Calendar
For size reasons the Snoopy Calendar program is on a separate page.Sample Assembler program deck
The following listing shows a card deck that compiles and runs an Assembler program that lists a deck of cards to the line printer.The following code Copyright (c) 2006 Kym Farnik. Code published under MIT license. See: http://www.opensource.org/licenses/mit-license.php
// JOB
// ASM
*LIST
* LCARD.ASM - LIST A DECK OF CARDS TO LINE PRINTER
*
* COPYRIGHT (C) 2006 KYM FARNIK.
* CODE PUBLISHED UNDER MIT LICENSE.
*
* PROGRAM
* NEW PAGE ON PRINTER
* A READ A CARD
* CONVERT FORMAT
* PRINT A LINE ON PRINTER
* GOTO A
*
START LIBF PRNT1 GOTO NEW PAGE ON 1132
DC /3100 PRINTER CHANNEL 1-NEW PAGE
*
NEXTC LIBF CARD0 READ FROM 1442 CARD READER
DC /1000 CONTROL TO READ
DC CBUFF STORE 80 COLUMNS
CINP LIBF CARD0
DC 0
B CINP LOOP UNTIL CARD IS READ
*
LIBF ZIPCO CONVERT CARD TO PRINTER
DC /1100 UNPACKED IN, PACKED OUT
DC CBUFF+1 INPUT BUFFER
DC PBUFF+1 OUTPUT BUFFER
DC 80 CHARACTER COUNT
CALL HLEBC HOLLERITH TO EBCDIC
*
LIBF PRNT1 PRINT 80 CHARACTERS
DC /2000 CONTROL CODE TO PRINT
DC PBUFF PRINT BUFFER
DC PERR PRINT ERROR
POUT LIBF PRNT1 CHECK FOR PRINT COMPLETE
DC 0
B POUT LOOP UNTIL COMPLETE
*
B NEXTC READ NEXT CARD
*
* DATA
*
CBUFF DC 80 80 COLUMNS PER CARD
BSS 80
*
PBUFF DC 40 40 WORDS 80 CHARACTERS
BSS 40
*
PERR DC 0
B I PERR THIS RETURNS TO THE
* PRINTER ERROR HANDLER
* WHICH WILL TERMINATE THE PROGRAM
*
END START PROGRAM ENTRY POINT
// XEQ
TEST DATA 1
HELLO WORLD
TEST DATA 2
Sample Fortran IV program deck
The following listing shows a card deck that compiles and runs a Fortran program and Fortran subroutine for the IBM 1130 when running DM2.The following code Copyright (c) 2005 Kym Farnik. Code published under MIT license. See: http://www.opensource.org/licenses/mit-license.php
// JOB // FOR *LIST SOURCE PROGRAM *ONE WORD INTEGERS C
--- C COMPUTE THE CRITIAL VALUES FOR A QUADRAITIC EQN C 0=A*X**2+B*X+C C RETURNS DISCRIMINANT, ROOTS, VERTEX, FOCAL LENGTH, FOCAL POINT C X1 AND X2 ARE THE ROOTS C
--- SUBROUTINE QUADR(A,B,C,DISCR,X1,X2,VX,VY,FL,FPY) REAL A,B,C,DISCR,X1,X2,VX,VY,FL,FPYC DISCRIMINANT, VERTEX, FOCAL LENGTH, FOCAL POINT Y DISCR = B**2.0 - 4.0*A*C VX = -B / (2.0*A) VY = A*VX**2.0 + B*VX + C FL = 1.0 / (A * 4.0) FPY = VY + FL FL = ABS(FL)
C COMPUTE THE ROOTS BASED ON THE DISCRIMINANT IF(DISCR) 110,120,130
C -VE DISCRIMINANT, TWO COMPLEX ROOTS, REAL=X1, IMG=+/-X2 110 X1 = -B / (2.0*A) X2 = SQRT(-DISCR) / (2.0*A) RETURN C ZERO DISCRIMINANT, ONE REAL ROOT 120 X1 = -B / (2.0*A) X2 = X1 RETURN
C +VE DISCRIMINANT, TWO REAL ROOTS 130 X1 = (-B + SQRT(DISCR)) / (2.0*A) X2 = (-B - SQRT(DISCR)) / (2.0*A) RETURN C C NEXT STORE SUBROUTINE ON DISK USING DUP END // DUP *DELETE QUADR *STORE WS UA QUADR // JOB // FOR *LIST SOURCE PROGRAM *IOCS(CARD,1132 PRINTER) *ONE WORD INTEGERS C
--- C PROCESS DATA CARDS WITH A,B,C C UNTIL A=0 C
---DATA ICARD,IPRT /2,3/ REAL A,B,C REAL DISCR,XR1,XR2,VX,VY,FL,FPY
WRITE(IPRT,901) 901 FORMAT('
--')C READ A B C, IF A=0 THEN EXIT 100 READ(ICARD,801)A,B,C 801 FORMAT(3F8.3)
C EXIT WHEN A IS ZERO IF (A) 110,9000,110
C PRINT A B C 110 WRITE(IPRT,902)A,B,C 902 FORMAT(' QUADRATIC A=',F8.3,' B=',F8.3,' C=',F8.3)
C COMPUTE AND PRINT THE CRITICAL VALUES CALL QUADR(A,B,C,DISCR,XR1,XR2,VX,VY,FL,FPY) WRITE(IPRT,903) DISCR 903 FORMAT(' DISCRIMINANT=',F9.4) WRITE(IPRT,904) VX,VY 904 FORMAT(' VERTEX X=',F9.4,' Y=',F9.4) WRITE(IPRT,905) FL 905 FORMAT(' FOCAL LENGTH=',F9.4) WRITE(IPRT,906) VX,FPY 906 FORMAT(' FOCAL POINT X=',F9.4,' Y='F9.4)
IF (DISCR) 120,130,140
C -VE DISCRIMINANT, TWO COMPLEX ROOTS 120 WRITE(IPRT,913) XR1, XR2 913 FORMAT(' COMPLEX ROOTS =(',F9.4,' +/-',F9.4,'I)') GO TO 200 C ZERO DISCRIMINANT, ONE REAL ROOT 130 WRITE(IPRT,912) XR1 912 FORMAT(' ROOT X =',F9.4) GO TO 200
C +VE DISCRIMINANT, TWO REAL ROOTS 140 WRITE(IPRT,911) XR1, XR2 911 FORMAT(' ROOTS X1=',F9.4,' X2=',F9.4) C --- GO TO 200
C END OF QUAD 200 WRITE(IPRT,901) GO TO 100
C END OF PROGRAM C DATA FOLLOWS XEQ CARD 9000 CALL EXIT END // XEQ +001.000+000.000+000.000 +001.000+002.000+003.000 +002.000+002.000+000.000 +002.000+000.000-004.000 +000.500+000.000-004.000 +000.250+002.000-002.000 -004.000+000.000-004.000 +002.730-007.200-003.750 +000.000+000.000+000.000
Sample APL \ 1130 session
The following image shows a simple APL \ 1130 session. This session was performed via the 1130 simulator available from IBM 1130.orgThe above session shows a signon, addition of the integers 1 to 100, generation of an addition table for the integers 1..5 and a sign off.
See also
External links
- IBM Historical site featuring the 1130
- IBM 1130.org Norm Aleks and Brian Knittel site which has significant information about the 1130 and a downloadable simulator that supports the DMS R2V12 and APL environments.
- www.ibm1130.net is Howard Shubs site dedicated to the 1130.
- Arnold Reinhold's personal account of the 1130. Text from here has been incorporated into this article with permission
- A set of PDFs made up of scanned IBM 1130 manuals
- Kym Farnik's page on Retro Computing specifically the 1130
- A discussion about the (then) Angle Park computing centre which was equipped with IBM 1130's
"IBM 1130"