HP Forum Archive 12

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matrix ROM fro the 9825 Message #1 Posted by olivier croissant on 2 May 2003, 1:10 p.m. Does anyone has a doc on the matrix ROM of the 9825A. or know how to use it ? By the way what is the diffeence between the 9825A and the 9825B from the point of view of the fonctionalities? do they accept the same ROM ? thanks

Re: matrix ROM fro the 9825 Message #2 Posted by Katie Wasserman on 2 May 2003, 11:06 p.m., in response to message #1 by olivier croissant Here's a link to Dave Meier's site. He's got a scanned copy of the 9825 QR that has the matrix commands in there -- all the ROM modules I think. http://www.n4mw.com/hp9825.htm

Re: matrix ROM fro the 9825 Message #3 Posted by Ellis Easley on 3 May 2003, 4:56 a.m., in response to message #2 by Katie Wasserman The 9825B comes with most of the standard ROMs inside, there are jumper options to select between two different plotter ROMs and to trade off ROM space for extra RAM. These ROMs are built in: String Variables, Advanced Programming, 9862A and 9872A Plotters, General I/O and Extended I/O. Matrix, Disk, and Systems Programming ROMs can be used with either 9825A or B. There are two different Disk ROMs, one can be used only in a 9825T. The Systems Programming ROM comes as a plug in cartridge for use in the 9825A; for the 9825B it is part of the internal large memory option that turns a 9825B into a 9825T. [That sounds like the Systems Programming ROM replaces the OS ROM on the right side of the 9825A, which the 9825B doesn't need since the ROMs are in the card cage.] This is from "HP 9825 Desktop Computer Operating and Programming Reference", 09825-90200 November 1980. It covers both A and B.

Re: matrix ROM fro the 9825 Message #4 Posted by Tony Duell (UK) on 3 May 2003, 8:20 p.m., in response to message #3 by Ellis Easley I beleive I have a 9825T -- at least it's got 64K RAM and the system programming ROM built in (and all the other ROMS, of course). The 2 memory boards (top 2 PCBs in the stack) are very different to those in other 9825s. The top PCB contains 32K RAM and all the ROMs (system ROM, and all the add-on ROMs). The lower PCB cotnaisn another 32K RAM and the memory paging circuitry. The system ROM cartridge slot on the RHS of the machine is not used at all on the 9825T. In fact it's disabled -- the appropriate track on the CPU board is cut (The track to enable the front ROM slots is cut too, but that's taken over by circuitry on the new memory boards, so these slots can be used). The only ROMs not built-in are the Matrix ROM and the Disk ROM, and I have both of those as cartridges.. I wonder. MAybe the 9825B does have the sytem programming ROM built in (i.e. the same ROMs as the 9825T), but you can't access it without the memory paging circuitry that's added when you add the second 32K of RAM.

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