Digital Equipment Corporation (DEC) PDP-1 and PiDP-1 Computer System Information
| ITT 7300 MOD II | Manufacturer |
| Automatic Data Exchange (ADX) System Model II | ITT Information Systems Division |
The hardware at left is an Automatic Send-Receive Device; hardware in center is the ITT 7301 MOD II Multiplex Message Processor; hardware on right is ITT 7321 Magnetic Tape Control Unit and the ITT 7320 Magnetic Tape Unit. The panel at the front of the ITT 7301 MOD II is used by the computer programmer and the panel in the center is used by the communications supervisor to provide status information. Photo by ITT Information Systems Division
APPLICATIONS
Applications include real-time message/data switching and information processing, command and control, management information, air traffic control, self-adaptive communications, process control and simulation.
This description pertains to the ITT 7301 MOD II multiplex message processor as used in the ITT 7300 ADX System.
PROGRAMMING AND NUMERICAL SYSTEM
| Internal number system | Binary |
| Binary digits/word | 18 |
| Binary digits/instruction | 18 |
| Instructions/word | 1 |
| Instructions decoded | 104 (expandable) |
| Arithmetic system | Fixed point |
| Instruction type | One address |
| Number Range | +131,071 to -131,071 |
| 5 Bits | 1 Bit | 12 Bits | 9 Bits | 9 Bits |
| OP Code | Indirect | Address | OP Code | Count |
| |
| 5 Bits | 1 Bit | 12 Bits |
| OP Code | Indirect | Address |
| Automatic built-in subroutines |
| | Read-in-mode (bootstrap) |
| | Parity Error Trap |
| | Priority Interrupt (multi-sequence) |
| Automatic coding |
| | Relocatable macro-based assembler |
| Registers and B-Boxes |
| Accumulator | Digital Data Display Buffer |
| In/Out Reg (LOPR) | Multi-sequencing Control |
| Memory Address | Register |
| Memory Buffer | Program Counter |
| Reader Buffer | Instruction Register |
| Punch Buffer | Core Memory |
| Keyboard Buffer | Typewriter Buffers |
| Printer Buffer |
| There is a one bit parity on words in storage. |
ARITHMETIC UNIT
| | Incl. Stor. Access Microsec | Excl. Stor. Access Microsec |
| Add | 24 | 3 (concurrent w/storage access) |
| Mult | 390 |
| Div | 528 |
| Construction (Arithmetic unit only) |
| Transistors | | 180 germanium PNP |
| Diodes | | 270 germanium |
Arithmetic mode Parallel Addition is concurrent with storage access. Multiplication and division is accomplished by sub routine using micro commands MUS and DIS. One's complement arithemetic is used. Timing Synchronous Operation Sequential on instruction, concurrent on Input/Output/Compute STORAGE No. of No of Access Medium Words Bin/Digits Microsec Magnetic Core 65,536 1,179,648 6 Magnetic Tape 5,337,600 96,076,800 192 Magnetic Drum 89,600 1,702,400 8,300 Magnetic Disc 1,572,864 29,884,436 25,000 Maximum core storage is given above. Capacity of tape is given for each reel. Magnetic Tape No. of units that can be connected 32 Units No. of chars/linear inch 556 Chars/inch Channels or tracks on the tape 7 Tracks/tape Blank tape separating each record 0.75 Inches Tape speed 75 Inches/sec Transfer rate 41,700 Chars/sec Start time 5 Millisec Stop time 5 Millisec Average time for experienced operator to change reel of tape 60 Seconds Physical properties of tape Width 0.5 Inches Length of reel 2,400 Feet Composition Mylar Magnetic tape access time assumes access in the middle of the tape (2,200 ft) from one end. Backward read available. INPUT Medium Speed Teletypewriter Lines Console Teletypewriter Data Speed Lines 2,400 baud Paper Tape Reader 10 - 400 cycles/sec Card Reader 800 cards/min In addition, there are manual console switches, magnetic tape, magnetic drum, magnetic disc, dual transfer path between machines for dual systems, and inquiry sets. Any available codes may be used at any commercial speeds. OUTPUT Medium Speed Teletypewriter Lines Console Typewriter Typing speed Data Speed Lines to 2,400 baud Paper Tape Punch 10 cps - 400 cps Card Punch 250 cards/min High Speed Printer 600 - 1,000 lines/min In addition, there are console and peripheral indicator lights, magnetic tape, magnetic drum, magnetic disk, dual transfer path between machines for dual systems, digital data display (direct-view CRT and projection). Any available code may be used at any commercial speed. CIRCUIT ELEMENTS OF ENTIRE SYSTEM Type Quantity Tubes 0 Diodes 22,209 Transistors 11,742 Magnetic Cores 1,245,184 (max) The cores are arranged in 19 arrays of 4,096 words each. CHECKING FEATURES Fixed checking features include memory parity and peripheral equipment status and error checks. Diagnostic routines are available as well as programmed message/data checking. POWER, SPACE, WEIGHT, AND SITE PREPARATION Power, cumputer 5.0 Kw Volume, computer 130 cu ft Area, computer 26 sq ft Room size 15 x 20 ft Floor loading 150 lbs/sq ft 3,000 lbs concen max Weight, computer 5,000 lbs Site preparation requirements False floor (or ducting) are required Air conditioning is required for 20,000 BTU/hr to maintain 60 - 80 F and 40% to 60% relative humidity. PRODUCTION RECORD Number produced to date 8 Number in current operation 6 Time required for delivery 9 months An average installation requires nine months to deliver hardware on-site, three months to cutover a completely operational real-time system. COST, PRICE AND RENTAL RATES Maintenance provided either as part of rental, or separate contract, if sale. PERSONNEL REQUIREMENTS One 8-Hour Two 8-Hour Three 8-Hour Shift Shifts Shifts Supervisors 1 2 3 Operators 1 2 3 Technicians 1 2 3 Training made available by the manufacturer to the users include a basic programing course, an advanced programming course, operator course, supervisor course, and and executive seminar in information processing.BRL 1964, ITT 7300 MOD II, starting page 0176 Maintenance training is provided on a contract basis. RELIABILITY, OPERATING EXPERIENCE In order to improve reliability, diagnostic programs, modular "motherboard" construction, self-check programming techniques, and better than 900 average effectiveness level with a dual system with automatic switchover from active main-frame to standby mainframe, are provided. ADDITIONAL FEATURES AND REMARKS Outstanding features include asynchronous Input Output/Compute, minimum of 256 external interrupts, interrupts assigned priorities, and multiple priority interrupts. Unique system advantages include external interrupts which "break into" processing, eliminating the need for time consuming scans, i.e., an on-demand system, designed for message/data and information processing use. Normal magnetic tape procedures may be followed for the handling of magnetic tape. Asynchronous operation of diverse input/output devices both remote, e.g., teletypewriter and inquiry sets, and local e.g., magnetic tape, disc, and drums as well as digital data display is possible in addition to the ability to handle diverse codes, speeds, formats from wide range of peripheral devices and/or computers. INSTALLATIONS U.S. Department of State (Paris) USAF Offutt AFB NASA, Huntsville, Alabama Aluminum Company of Canada American Cable and Radio Corporation Eastern Air Lines, New York City Standard Telephones and Cables Limited, London