View source for PDP-1-X

The '''PDP-1-X''' was a heavily modified [[PDP-1]] created at [[MIT]]'s [[RLE]].

Notable differences are:

* the addition of operating modes to the [[Central Processing Unit|CPU]] (to support [[time-sharing]]): 'TS Off', 'TS Debug', 'Exec' (used for the [[kernel]]), and 'User';
* additional [[instruction]]s;
* the addition of an [[index register]];
* an [[input/output|I/O]] [[bus]] for connection of [[peripheral]]s.

==External links==

* [http://www.bitsavers.org/pdf/mit/rle_pdp1/ RLE PDP-1] - Original RLE PDP-1 documents
** [http://www.bitsavers.org/pdf/mit/rle_pdp1/memos/MIT_PDP-1_Memos.txt PDP-1 Timesharing System Memos]
** [http://www.bitsavers.org/pdf/mit/rle_pdp1/memos/pdp38_newInstrs_jun66.pdf Modes, Registers, New Instructions, and Traps and Interrupts in the PDP-1-X]
* Machine readable copies of paper tapes and DECtapes from MIT:
** [http://bitsavers.org/bits/MIT/rle_pdp1x/ MIT RLE PDP1X]
** [http://bitsavers.org/bits/DEC/pdp1/papertapeImages/ DEC PDP1 paper tape images]

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[[Category: DEC Systems]]