[sebhc] introduction

Jim Battle frustum at pacbell.net
Wed Jun 29 01:56:03 CDT 2005

Hello, sebhc list members.

I'm new here, and new to the heath scene.

Recently I was given three H89 computers, an H47 dual 8" disk drive unit, an H77 
dual 5.25" disk drive unit, along with some disks and docs.

One machine has a single full sized 5.25" drive and it gets the H: prompt, and I 
can boot off of the internal drive (it is set up as the secondary drive).  I 
have only one disk that wants to boot from that drive, running CP/M 1.34 or 
somesuch.  I tried hooking up the H77 to it but the H77 is wired up such that 
drive 0 in the external drive is mapping to drive 0 of the internal drive. 
Unfortunately, one of the 8" disk drives in the H47 box had its door broken off 
during shipping (my sister decided she didn't want it sitting in her basement 
until christmas, so she "packed" it and shipped it :-( )

The second machine is for parts it appears -- it has no disk drives, is missing 
some keys, and there is nothing on the CRT when I power it up or reset it. 
Perhaps it requires a simple fix, but for now, I'm assuming it is for spare parts.

The third machine has two half high 5.25 inch disk drives.  Many of those 5.25" 
disks that weren't readable in the first machine had "CDR" written on the label, 
and I had no idea what that meant.  When I opened the third machine, floating 
around inside the case was a two board sandwich that was made by "CDR systems 
inc".  It contains a Z80 and what might be 1 MB of RAM.  THe other big chips on 
it are a national semi DP8409AN-2 (which I think is a dram controller), a 
national semi MM58167AN real time clock chip, and a socket for a 40 pin device 
which is empty.  there is a 40 pin ribbon cable from one of these CDR boards to 
the original Z80 socket on the main CPU board.  The reason those boards and the 
other I/O cards were floating around was that this machine is missing the card 
cages that should be holding in those cards.  I guess I have found the first use 
for my parts machine.  :-)

I've had the courage to try the third machine after reseating the floating cards 
like I think they should be and indeed it works -- there is a 1MB RAM disk and 
it runs a 63K CP/M.  The disk drive capacity is 780KB according to D.COM.  One 
of the disks has the CBIOS for the CDR system.  When you boot a CDR disk, it 
says: do you want a ram disk or not?  If not, then the floppies are drives A and 
B.  If you do request the ram disk, then there are other questions to answer 
(should I wipe what is already in the RAM disk (it is battery backed up I 
guess), do you want one or two RAM disk partitions).  If there is one ram disk 
of nearly 1MB, then the physical first floppy becomes drive b:.

None of the disks that boot boot into HDOS.  Perhaps some of the 8" disks do, 
but that will have to wait for another night.

The docs that came with the machine include
	Heathkit Manual for the DIGITAL COMPUTER H88 assembly (595-2267)
	Heathkit Manual for the DIGITAL COMPUTER H88 operation (595-2268)
	Heathkit Manual for the DIGITAL COMPUTER H89A operation (595-2766-04)
	Heathkit Manual for the FLOPPY DISK Model H47 (595-2467-01)
	Z89-47 accessory (595-2473-02)
	H-88/H-89/Z-89/Z-90 Configuration Guide (597-2571)
	Instructions for the PROM UPGRADE ACCESSORY Model H88-7 (595-2547)
	Modification Kit for the H88/WH89 COMPUTER Model H88-6 (597-2171)
	Instructions for 16K MEMORY EXPANSION ACCESSORY Model WH88-16 (595-2489)
	Monitor MTR-89 (595-2508) (this is a rom source listing)
	BIOS LISTING for CP/M 2.2.03 (595-2775)

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