Difference between revisions of "UNIBUS boot ROMs"
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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; it contained only 32 words of memory. The second was the [[M9301 ROM]] card; it had a capacity of 512 words, using [[PROM]] chips. The third was the [[M9312 ROM]] card, which also had a capacity of 512 words. | The first was the [[BM792 ROM]] card, which used individual diodes in an array to represent individual bits; it contained only 32 words of memory. The second was the [[M9301 ROM]] card; it had a capacity of 512 words, using [[PROM]] chips. The third was the [[M9312 ROM]] card, which also had a capacity of 512 words. | ||
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In both of the latter two cards, the entire ROM contents were directly visible on the UNIBUS, not through a window. | In both of the latter two cards, the entire ROM contents were directly visible on the UNIBUS, not through a window. | ||
| − | There was also | + | There was also another early [[DEC card form factor|quad]] ROM card, the [[M873]], but almost next to nothing is currently known about it; apparently it contains 128 words, using 2 of the ROM chips like those in the M9301. |
| − | the [[M873 | ||
Revision as of 20:54, 26 March 2016
DEC produced several generations of UNIBUS ROM boot cards.
The first was the BM792 ROM card, which used individual diodes in an array to represent individual bits; it contained only 32 words of memory. The second was the M9301 ROM card; it had a capacity of 512 words, using PROM chips. The third 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.
There was also another early quad ROM card, the M873, but almost next to nothing is currently known about it; apparently it contains 128 words, using 2 of the ROM chips like those in the M9301.
