PDP-8/I: Difference between revisions
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{{Infobox Machine | {{Infobox Machine | ||
| name = PDP-8/I | | name = PDP-8/I | ||
| image = PDP-8'I FrontPanel.jpg | |||
| caption = PDP-8/I front panel | |||
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| ram = Maximum of 32 kwords in eight 4 kword banks | | ram = Maximum of 32 kwords in eight 4 kword banks | ||
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| Line 22: | Line 22: | ||
}} | }} | ||
The '''PDP-8/I''' was introduced in 1968 as the successor to the [[PDP-8]]. It was constructed out of [[Transistor-transistor logic|TTL]] [[integrated circuit|ICs]] on M-class [[FLIP CHIP]]s. | The '''PDP-8/I''' was introduced in 1968 as the successor to the [[PDP-8]]. It was constructed out of [[Transistor-transistor logic|TTL]] [[integrated circuit|ICs]] on M-class [[FLIP CHIP]]s - mostly early [[DEC card form factor|standard-length single-height]] (width) ones, with a few dual-height. It was the first [[Digital Equipment Corporation|DEC]] computer to be built using ICs. | ||
Options included: | Options included: | ||
* KA8/IB Positive I/O Bus Interface, to allow use of newer PDP-8 devices | * KA8/IB Positive I/O Bus Interface, to allow use of newer PDP-8 devices | ||
* MC8/I Memory Extension Control, | ** DW08A Negative I/O Bus Conversion Option (on systems with a KA8/I, allows use of older PDP-8 devices) | ||
* MP8/I Memory Parity | ** DW08B Positive I/O Bus Conversion Option (on systems without a KA8/I, allows use of newer PDP-8 devices) | ||
* KE8/I Extended Arithmetic Element, which supported [[hardware]] integer multiplication and division, one-[[bit]] double-word shifts, and [[normalization]] | ** DW8-E [[OMNIBUS]] Interface (converts the positive bus of an 8/I) | ||
* MC8/I Memory Extension Control, [[bank switching]] needed to support more than 4K [[word]]s of memory | |||
* MP8/I Memory [[Parity]] | |||
* KE8/I [[Extended Arithmetic Element]], which supported [[hardware]] integer multiplication and division, one-[[bit]] double-word shifts, and [[normalization]] | |||
* KT8/I Time Sharing Hardware Modification, which allowed the computer to operate in either Executive Mode or User Mode | * KT8/I Time Sharing Hardware Modification, which allowed the computer to operate in either Executive Mode or User Mode | ||
It could perform an addition to the [[accumulator]] in 3.0 μseconds, and a 12 by 12 bit multiplication with 24 bit result in 6.0 μseconds, using the math extension hardware. | It could perform an addition to the [[accumulator]] in 3.0 μseconds, and a 12 by 12 bit multiplication with 24 bit result in 6.0 μseconds, using the math extension hardware. | ||
The MC-8/I had three 3-bit [[register]]s: the Instruction Field and associated Instruction Buffer, and Data Field, which could be loaded either manually from the [[front panel]], or under program control (by the Change Instruction Field - something of a misnomer, as it was actually the IB which was loaded - and Change Data Field [[instruction]]s). The IB contents were loaded into the IF by a [[jump]] or [[subroutine]] call. | |||
==Images== | |||
[[Image:PDP-8'I HoppeLighted.jpg|left|thumb|400px|PDP-8/I of the Göttingen Computer Club in Göttingen, Germany]] | |||
<br clear=all> | |||
[[:File:PDP-8'I ComputerCabinettGöttingen.jpg|Another image]] | |||
==External links== | |||
* [http://www.bitsavers.org/pdf/dec/pdp8/pdp8i PDP-8/I] - Original PDP-8/I documents | |||
{{Nav PDP-8}} | {{Nav PDP-8}} | ||
[[Category: PDP-8s]] | |||
Latest revision as of 12:10, 14 July 2023
| PDP-8/I | |
 PDP-8/I front panel | |
| Year Introduced: | 1968 |
|---|---|
| Form Factor: | minicomputer |
| Word Size: | 12 |
| Logic Type: | TTL |
| Design Type: | clocked random logic |
| Clock Speed: | 333KHz |
| Memory Speed: | 1.5 μseconds |
| Physical Address Size: | 32KW (requires optional MC8/I) |
| Virtual Address Size: | 4KW |
| Memory Management: | bank selection, CPU mode |
| Bus Architecture: | negative I/O bus |
| Operating System: | TSS/8. Disk Monitor System |
| Predecessor(s): | PDP-8 |
| Successor(s): | PDP-8/E |
The PDP-8/I was introduced in 1968 as the successor to the PDP-8. It was constructed out of TTL ICs on M-class FLIP CHIPs - mostly early standard-length single-height (width) ones, with a few dual-height. It was the first DEC computer to be built using ICs.
Options included:
- KA8/IB Positive I/O Bus Interface, to allow use of newer PDP-8 devices
- DW08A Negative I/O Bus Conversion Option (on systems with a KA8/I, allows use of older PDP-8 devices)
- DW08B Positive I/O Bus Conversion Option (on systems without a KA8/I, allows use of newer PDP-8 devices)
- DW8-E OMNIBUS Interface (converts the positive bus of an 8/I)
- MC8/I Memory Extension Control, bank switching needed to support more than 4K words of memory
- MP8/I Memory Parity
- KE8/I Extended Arithmetic Element, which supported hardware integer multiplication and division, one-bit double-word shifts, and normalization
- KT8/I Time Sharing Hardware Modification, which allowed the computer to operate in either Executive Mode or User Mode
It could perform an addition to the accumulator in 3.0 μseconds, and a 12 by 12 bit multiplication with 24 bit result in 6.0 μseconds, using the math extension hardware.
The MC-8/I had three 3-bit registers: the Instruction Field and associated Instruction Buffer, and Data Field, which could be loaded either manually from the front panel, or under program control (by the Change Instruction Field - something of a misnomer, as it was actually the IB which was loaded - and Change Data Field instructions). The IB contents were loaded into the IF by a jump or subroutine call.
Images
External links
- PDP-8/I - Original PDP-8/I documents
| v • d • e PDP-8 Computers, Software and Peripherals |
|---|
| PDP-8s: PDP-5 • PDP-8 • LINC-8 • PDP-8/S • PDP-8/I • PDP-8/L • PDP-12 • PDP-8/E • PDP-8/F • PDP-8/M • PDP-8/A
Workstations: VT78 Also: PDP-8 family • PDP-8 architecture • PDP-8 Memory Extension units |
