Path: utzoo!attcan!uunet!know!zaphod.mps.ohio-state.edu!swrinde!ucsd!ucbvax!XEROX.COM!Sprague.Wbst311 From: Sprague.Wbst311@XEROX.COM Newsgroups: comp.os.cpm Subject: Xerox 820-II cards Message-ID: <"26-Oct-90.10:43:22.EDT".*.Michael_D._Sprague.wbst311@Xerox.com> Date: 26 Oct 90 14:43:22 GMT Sender: daemon@ucbvax.BERKELEY.EDU Reply-To: Sprague.Wbst311@xerox.com Organization: The Internet Lines: 47 Grumble! This bounced the first time. It's a little late, but still applies. -------------------------------- In reference to the card in Steve's Xerox 820-II, and in the spirit of general information sharing (I saw some incorrect info), I have written the following note. :-) --------- As has been pointed out, the Xerox 820 has NO card edge slots. The 820-II, 16/8's or what have you ... the CPU board is the same for all of them, had two card edge slots near the left side. There were only 4 cards for Xerox 820's made in the USA. Two of them were for the left card connector and two of them were for the right. In all cases, when I say right and left, it will be as if I was looking into the machine from the rear. The left slot is for the drive controller. It will contain either a floppy controller card (works with both 5.25" or 8" drives), a hard drive interface card (8" drives only), or NO board if it's a 16/8 machine with a DEM (Disk Expansion Module). Off the top of my head, the hard drive card is maybe 3" tall, while the floppy controller is maybe 4" tall. NEVER connect the floppy controller card to a hard drive, as you will blow the floppy/hard drive controller board down the line. I do not think connecting a hard drive interface board with floppy's will cause any damage, but I wouldn't chance it. The right slot will contain NO board if it's a standard Xerox 820-II, a 16/8 board if it's a 16/8 (that's an 8086 system on a card, for those of you who do not know), or a DEM buffer board if this is a 16/8 with DEM. Now that I think of it, there was also a 256K memory expansion board for the 16/8, which plugged directly into the 16/8 board. Very hard to find and expensive. I have seen notes where Rank Xerox (in England) may have made some additional cards which went into the DEM. (Note: The DEM has a card cage which can hold 4 or 5 cards, one of which would be the 16/8 card.) There may have been an RX memory expansion card (256K) for the 16/8, and there may have been an RX fancy video graphics board. The most notable incorrect things I saw was that sombody said the 16/8 board contained an 8088, and that the DEM connected up to the 16/8 board. ~ Mike (Sprague.Wbst311@Xerox.Com)