rusty@cadnetix.COM (Rusty) (04/04/89)
Well, I just bought myself a nice hard disk controller for my S100 system.
Having looked over the CPM manual for a bit, it seems to me that I *should*
be able to accomplish the task of adding the controller and hard disk to
my system.
When I had my Kaypro 10, I seem to recall that it could boot off of either
the hard disk OR a floppy. However, one time I tried to make my system
boot off of my ramdisk with much less than pleasant results :-).
I figured at the time that it had to do with booting from something other
than drive A. However, as I think about the Kaypro 10 I doubt it.
So, enough rambling, down to the question for the net:
Has anyone else added a hard disk to a CP/M system which was not originally
configured for a hard disk? Can I do the trick that Kaypro did and boot
from either flops or hard? Any words of wisdom? (Other than "Don't do it!" :-)
TIA, very much. (*)
Rusty.
(*) TIA - thanks in advance.
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Rusty Carruth UUCP:{uunet,boulder}!cadnetix!rusty DOMAIN: rusty@cadnetix.com
Daisy/Cadnetix Corp. (303) 444-8075\ 5775 Flatiron Pkwy. \ Boulder, Co 80301
Radio: N7IKQ 'home': P.O.B. 461 \ Lafayette, CO 80026rlb@cs.odu.edu (Robert Lee Bailey) (04/05/89)
In article <7316@cadnetix.COM> rusty@cadnetix.COM (Rusty) writes: > >Well, I just bought myself a nice hard disk controller for my S100 system. >Having looked over the CPM manual for a bit, it seems to me that I *should* >be able to accomplish the task of adding the controller and hard disk to >my system. > > >So, enough rambling, down to the question for the net: > >Has anyone else added a hard disk to a CP/M system which was not originally >configured for a hard disk? Can I do the trick that Kaypro did and boot >from either flops or hard? Any words of wisdom? (Other than "Don't do it!" :-) > I have a Xerox 820-1 single board CP/M computer. When I got it, it was not expandable to allow adding a hard disk. After checking around a bit, I found an inexpensive (for the time) 5MB hard disk ($99) and a SCSI HD controller (also $99). Now the Xerox 820 did not have a SCSI interface, so, I had to build my own adapter as well as write my own HD driver. The hardware adapter was not very sophisticated (i.e. not interrupt driven). I just wire wrapped an adapter that plugged into the Z-80 socket. This allowed me to 'tap' the I/O and data lines that I needed for the SCSI controller. I added some TTL logic to decode the address that I wanted to use for the controller and then began to write the software to access the SCSI port. I wrote the necessary routines and added them to my BIOS. I probably could have made it boot off of the HD, but, that would have required me to patch the ROM. Since I didn't have access to an EPROM burner, I elected to use a hybrid method. What I did was to modify the boot tracks of the floppy so that instead of loading CP/M (BDOS & BIOS) from the floppy, I loaded the HD driver. After the driver was in memory, I loaded CP/M from the hard drive (I SYSGENed a modified boot track onto the HD). I also faked out CP/M to make my HD (drive E:) my default drive. So, when I booted the system, it automatically came up logged into the HD. Using this method, only a few sectors were loaded from floppy, and then the rest of the booting occured from the HD. While this was not the optimum way to do it, for me it proved to be a viable way to get a HD up and running with minimal modifications to my existing hardware & software. Bob Bailey
uucp@lakart.UUCP (comp.os.cpm gateway) (04/07/89)
rusty@cadnetix.com asks: > Has anyone else added a hard disk to a CP/M system which was not > originally configured for a hard disk? Can I do the trick that > Kaypro did and boot from either flops or hard? Any words of > wisdom? (Other than "Don't do it!" :-) I can only speak of my case with a Televideo TS803 from a semi-hypothe- tical point of view. The story - I have a TS803 (non hard disk version) and I added a mini-winnie hard disk to it. So in response to your first question I have added a hard disk to a floppy only system. To explain what is necessary: all you have to do is to make the BIOS know about the hard disk - add the necessary tables, and the code to read / write it, and you can run from the hard disk. That part is done, and works - i.e. I have a system with the original floppies, and a hard disk "grafted" on. As to booting it: I don't know how you work, but the boot process in the 803 goes like this: The boot rom reads drive A:, Track 0, Sector 0 into ram at a particular spot, then jumps to that code. So I can put any bootstrap loader I like into that 256 bytes of code - as it is, I just read the operating system from the remainder of track 0 and track 1, and jump to the cold boot entry point of the BIOS. Assuming you work like this, if you can read and write the hard disk OK, it can be done as a two step operation. Firstly write a boot sector loader that will be pulled from floppy by the boot rom, that loads CCP / BDOS / BIOS from the hard disk, and save that onto a floppy. Now when you boot that floppy, the boot sector (T 0 S 0) comes off the floppy, drops into ram, and is executed, but it goes to the hard disk to get the rest of the operating system. Next step is to write this same boot sector somewhere on the hard disk, and (here comes the hard part :-) ) modify the boot rom to read from the hard disk. I plan to go about doing this for my system in the above manner, and also plan to arrange that the rom looks first to see if a floppy is present: if so boot from it. If not it then looks at the hard disk to see if it can find anything there. So if I reset with a floppy in drive A: I'll boot from the floppy, otherwise I'll boot from the hard disk. -- dg@pallio.UUCP - David Goodenough +---+ IHS | +-+-+ ..... !harvard!xait!lakart!pallio!dg +-+-+ | AKA: dg%pallio.uucp@cfisun.cfi.com +---+
mlinar@eve.usc.edu (Mitch Mlinar) (04/09/89)
In article <7316@cadnetix.COM> rusty@cadnetix.COM (Rusty) writes: > >Well, I just bought myself a nice hard disk controller for my S100 system. >Having looked over the CPM manual for a bit, it seems to me that I *should* >be able to accomplish the task of adding the controller and hard disk to >my system. > >Has anyone else added a hard disk to a CP/M system which was not originally >configured for a hard disk? Can I do the trick that Kaypro did and boot >from either flops or hard? Any words of wisdom? (Other than "Don't do it!" :-) Quite a few of us have added bootable hard drives to our non-hard drive systems. There is only one way to do it: replace the ROM inside your machine so that it uses the hard disk controller for boot. Even better, is to have it look for a hard drive and, failing that, to look for a floppy. This is what the Kaypro 10 did and essentially all after-market upgrade ROMs for the Z80 machines (Xerox, Kaypro, Morrow, Osborne) do for you. Since your machine is an S100, you will probably have to "roll you own". Given that you have the source for the current boot ROM, enough room for the code, and an EPROM burner, you are most of the way there. -Mitch
mikes@ncoast.ORG (Mike Squires) (04/10/89)
In article <7316@cadnetix.COM> rusty@cadnetix.COM (Rusty) writes: > >Well, I just bought myself a nice hard disk controller for my S100 system. >Having looked over the CPM manual for a bit, it seems to me that I *should* >be able to accomplish the task of adding the controller and hard disk to >my system. The vendor of the HDC usually provided a BIOS in source that had to be added to the system BIOS to connect the drive. I would assume that it would be possible to boot off the HD, but none of the systems I every used did (S-100 systems with Advanced Digital, Morrow, and Jade HDC's). The AD HDC came with autoinstall software; the other two required revisions of the BIOS. One of the last books about CP/M to be published had a BIOS based on the JADE controller. I believe that old SIG/M and CP/MUG disks may also have BIOSes. Mike Squires Allegheny College Meadville, PA 16335 814 332 3347 uucp: ..!cwjcc!ncoast!{mikes,peng!sir-alan!mikes} or ..!{pitt,uunet}!sir-alan!mikes BITNET: mikes%sir-alan@pitt.UUCP (VAX) MIKES AT SIR-ALAN!PITT.UUCP (IBM) Internet: sir-alan!mikes@uunet.uu.net or mikes@NCoast.ORG