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Re: [N8VEM-S100:2614] Show and Tell - New user S100 system up & running (well sorta !)

Hi Leonard,
Just thought I would post you some feedback on how I have got on over the last few weeks bringing the Z80 up to a CP/M prompt.
I started out by reading John's excellent article on 'Bringing Up CPM3 For The First Time On a IDE Hard Disk Based System'
I read it several times then realised that I was in a chicken & egg situation as I didnt have access to a CP/M system to get the system track (CPMLDR) laid down let alone getting the other files onto my CF card. The utility that John provides HSYSGEN.COM still needs to run on a CP/M system, so after searching this forum I found an old post where a member mentioned a utility HxD (sorry cant remember who it was but thanks for the light bulb moment).
This utility is a Hex Editor that allows you to work with disk file images and CF cards directly, the only problem standing in the way is that the current method of writing to disk in LBA mode leaves holes in the disk sector map. This made direct sector editing/writing somewhat difficult so the easiest option for me was to rewrite the wrlba: routine in John's ASM files to convert the CP/M track and sector requests into a linear LBA sector number and remove the holes, making disk sector editing a possibility now that i can predict where to place the data.
I must point out that there are some limitations to my solution, in that the disk configuration must be 256 tracks, 64 Sectors, and 512 bytes/sector (specifically 64 sectors) which gives a 8MB drive but I have a few ideas that may fix this if it ever becomes necessary.
Anyway to cut a long story short I now have the system up to a CP/M 3.0 (Non-banked) command prompt and am thinking about moving on to a 'Banked' setup before dragging all the utility files across from the Altair simulator.
I have spent the last few days writing up my process and gathering together all the file sets that I used in getting my system working and have uploaded it as a single ZIP file "CPM3_LBA.ZIP" to my N8VEM workspace
I have also uploaded two MSword documents (included within the ZIP archive)  'Z80_LBA_Addressing.DOC'  and  'Z80 CPM3.0 Build.DOC' so that you can read these first. I hope this information may be of interest and of use to you and others in the future.
David Fry

On Monday, March 3, 2014 11:02:56 PM UTC, mathman wrote:



I'm about where you are. My lab's being updated and painted etc. right now, and when done, I'll be looking to get CPM loaded (CPM2?).

Please let us know how you make out with CPM3!




From: n8ve...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of David Fry
Sent: Monday, March 03, 2014 8:58 AM
To: n8ve...@googlegroups.com
Subject: [N8VEM-S100:2614] Show and Tell - New user S100 system up & running (well sorta !)


Hi all,


8 months after my first contact/enquiry to John Monahan regarding building a S100 computer I now have the hardware up and running as far as the Z80 monitor.


The boards currently build and fitted are:-

S100 V2 Z80 CPU card (running at 6mhz at the moment)

S100 V1 RAM&ROM card

S100 V2 IDE Interface card

S100 V1 Console I/O card

S100 V2 Bus extender card (just for the reset button)


The main power supply rails are switch mode (+8v, +16v, -16v) with secondary linear regulators (+5v, +12v) to power the onboard hard disk/floppy drive.

The outer case metalwork (extruded sides & aluminium base) was purchased from http://www.modushop.biz/ecommerce/index_l2.php

it's essentially case metalwork for audio/hifi projects but I liked the idea of sliding the power supply modules & disk drives into the 'T' slotted sides and it allows me to change my mind on drives etc... over time.


The 10 slot active terminated backplane came from Herb Johnson (Retrotechnology.com) 


I have uploaded a couple of pictures to the N8VEM workspace to encourage others who are still working on their first S100 system



I'd like to thank both John and Andrew for the hours of fun so far in putting this system together, i'm sure it's not all going to be plain sailing though which brings me to my first question.


I have noticed in the Z80 monitor (v5.02) that once the screen is filled with characters and starts to scroll the cursor prompt disappears !!, the monitor still responds to commands though and all functionality otherwise seems fine. Can anyone else replicate/confirm this, it's not a biggie but thought I would mention it.


Now I'm off to try and burn the IDE diagnostic test utility onto an EEPROM to check out the IDE board before working out how to get CP/M 3 up and running.


regards and happy soldering


David Fry


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