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- Path: sparky!uunet!usc!zaphod.mps.ohio-state.edu!mips!pacbell.com!att!ucbvax!XEROX.COM!Sprague.Wbst311
- From: Sprague.Wbst311@XEROX.COM
- Newsgroups: comp.os.cpm
- Subject: Re: Xerox 16/8??
- Message-ID: <"20-Jul-92..9:24:48.EDT".*.Michael_D._Sprague.wbst311@Xerox.com>
- Date: 20 Jul 92 13:24:48 GMT
- Sender: usenet@ucbvax.BERKELEY.EDU
- Reply-To: Sprague.Wbst311@xerox.com
- Organization: The Internet
- Lines: 90
-
-
- Get in touch with me (EMail or phone), and I'll see if we can get you some
- documentation for your computer.
-
- The Xerox 16/8 is nothing more than a Xerox 820-II with an 8086 single boad
- computer (the 16/8 card) plugged into the expansion slot. Both are
- independent, with their own ROM, RAM, etc, but they share the drives and
- console.
-
- The system boots up in stnadard CP/M, and by running a few commands, can switch
- into concurrent CP/M-80 / CP/M-86 mode. It also ran vanella MS-DOS (not
- PC-DOS), but this (IMOHO) is useless on the 8" drive machine, and is of
- questionable value on the 5.25" 16/8 DEM since most MS-DOS programs are written
- for PC-DOS. For that matter, I don't think CP/M-86 is of much use either, due
- to the lack of available software.
-
- > I am looking for any info about the hardware, schematics etc. I am also
- > looking for info on video mode programming (escape codes etc.).
-
- Drop me a line. I'll see about getting you a copy of the documentation.
-
- > Is it Xerox 820 compatible?
-
- Yes, in CP/M mode, but it's somewhat better than the old 820. The 820-II and
- 16/8 support double density disks .... something you don't get on the old 820
- without a spcial harware upgrade.
-
- > It tells me I have 60K bios, but how much memory is there really?
-
- On the motherboard (containing the Z80), there is 64K of RAM (not BIOS), 60K of
- which is available for CP/M. The 16/8 board usualy contains 128K of RAM, but
- would be 256K if it has the RAM expansion board. This RAM is available to
- CP/M-86 and/or MS-DOS.
-
- > Does anyone know if I can get the 8" single sided diskettes?
-
- Check out computer flea markets and the like. I think I might have some, but I
- am not sure.
-
- > Is it possible to expand the disk storage? Double sided? 5-1/4"?
-
- I am going to answer this for all three of the Xerox machines, since the 16/8
- can be used as an 820-II. Also note that a single sided 8" floppy holds more
- data than a double sided 5.25" one. A double sided 8" floppy on the Xerox
- 820-II or 16/8 held almost 1 Meg.
-
- The Xerox 820 supported two 8" or 5.25" drives. Single density, but the disks
- could be single of double sided. (Some with older BIOS supported three drives,
- but they were only single sided). 5.25" disks were next to useless due to
- limited storage.
-
- The Xerox 820-II supported two 8" or 5.25" drives. Single or double density
- and single or double density.
-
- The 16/8 could support two 8" or two 5.25" disks. It's not quite as simple as
- that though. CP/M-86 and MS-DOS on the 16/8 would ONLY support the 5.25" DEM
- (Disk Expansion module), and would NOT boot on the normal 5.25" drives, though
- 820-II disks would. Note that to install the DEM, the Disk controller would be
- removed (as there was already a Western Digital Hard/Floppy controller in the
- DEM), and a buffer board would be added in the 820's expansion slot. The 16/8
- board was installed in a card cage in the DEM.
-
- There is one pin on the Disk interface (on a non 16/8 DEM machine) that
- determines if 8" or 5.25" disks are installed. If I remember right, it's pin
- 2, and if grounded, it means that 5.25" disks are installed. In all cases
- (except the early 820's) the Xerox machine ONLY supports two floppies.
-
- Last, while it is not simple, I have converted an 820-II to use 5.25" High
- Density disk drives. As far as the 820-II is concerned, it has 8" drives
- installed, and treates them as such. The tricky part is what to do with Drive
- Ready.
-
- > How do I program serial output baud rates, etc.?
-
- There is a program on the Boot disk called CONFIGUR. It is used to set up the
- serial ports, the floppy step rate, keyboard interface (7 or 8 bits) and a few
- other things.
-
- > It is a Xerox (diablo) daisy wheel printer. anyone know about it?
- > It said, on the plate by the dip switch, something about having a
- > "Special baud rate" it also has 300 and 1200.
-
- I don't know about a special baud rate, but the 820-II has no trouble with a
- printer up to 9600 baud (I have never taken it any further). Some of the 820's
- documentation talks about the printer.
-
- ~ Mike (sprague.wbst311@xerox.com)
-
- Work Phone: (716) 422-0472
- Home Phone: (315) 986-9863
-