UNIBUS boot ROMs: Difference between revisions
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DEC produced | DEC produced several generations of '''[[UNIBUS]] [[Read-only memory|ROM]] boot''' cards. | ||
The first was the [[BM792 ROM]] card, which used individual diodes in an array to represent individual bits | * The first was the [[BM792 ROM]] [[DEC card form factor|quad]] card, which plugged into an [[Small Peripheral Controller|SPC]] slot; it used individual diodes in an array to represent individual bits, and contained only 32 words of memory. | ||
* The second was the [[BM873 ROM]], also a quad card used in an SPC slot; it contains 128 words, using 2 [[PROM]] chips. | |||
* The third was the [[M9301 ROM]] card, a dual card intended for use in the top two rows of a [[Modified UNIBUS Device|MUD]] slot; it had a capacity of 512 words, using four chips like those in the BM873. | |||
the [[ | |||
* The last was the [[M9312 ROM]] card, which also had a capacity of 512 words. | |||
In both of the latter two cards, the entire ROM contents were directly visible on the UNIBUS, not through a window, unlike later, larger [[QBUS]] ROM cards. | |||
[[Category: UNIBUS ROMs]] | |||
Latest revision as of 23:12, 16 December 2018
DEC produced several generations of UNIBUS ROM boot cards.
- The first was the BM792 ROM quad card, which plugged into an SPC slot; it used individual diodes in an array to represent individual bits, and contained only 32 words of memory.
- The second was the BM873 ROM, also a quad card used in an SPC slot; it contains 128 words, using 2 PROM chips.
- The third was the M9301 ROM card, a dual card intended for use in the top two rows of a MUD slot; it had a capacity of 512 words, using four chips like those in the BM873.
- The last was the M9312 ROM card, which also had a capacity of 512 words.
In both of the latter two cards, the entire ROM contents were directly visible on the UNIBUS, not through a window, unlike later, larger QBUS ROM cards.
