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Bootstapping Cromemco 4FDC

The progress has been slow on the Cromemco 4FDC system. I am going to put the 8" disks on the shelf for now and focus on 5" disks and getting a stable system running.
Right now I have 2 usable 5" floppy disks created. The CDOS 0020 image I was given and a 16K basic IMD image that is bootable and has basic.
Using basic I cannot save files. I keep getting an "error 141 no channel" when I try to save.

I can INIT disks and I have been able to XFER files from drive A to B. that is about as far as I have been.
Currently I am trying to use the Gotek as drive B but all of the images I have used do not seem to work. CDOS gives seek errors 32 and 36 hex which indicate it can't find the first track or read it. here is my gotek img.cfg for single sided, single density DSK images:
[::92160]
description = double sided single density 5.25" CP/M disks
cyls = 40
heads = 1
interleave = 3
secs = 18
bps = 128

The images I am using are from the Z80 pack.

www.autometer.de/unix4fun/z80pack/ftp/cromemco/
I have tried the cdos 00205, 1075, 2585
These images are 92160 bytes in size which calculates to single sided single density.

Are there other images on this site I can try with the 4FDC controller or does someone know where there may be other images to try?

Also the following questions:
Am I using the DSK files with the Gotek right?
1) Can I use IMD files?
2) Is there an way on linux to see what the dsk files look like?(or windows if needed) I guess I assume they are raw but maybe a special signature or what format CP/M is looking for to make a disk format valid?
I guess any help with getting images working would be great.
3) Should I be using the Z80 pack and creating my disks that way?
4) Can I use CP/M-86 to make disk for the s-100 system?

Thank you everyone for all of the help.
 
Endersending said:
The progress has been slow on the Cromemco 4FDC system. I am going to put the 8" disks on the shelf for now and focus on 5" disks and getting a stable system running.
Right now I have 2 usable 5" floppy disks created. The CDOS 0020 image I was given and a 16K basic IMD image that is bootable and has basic.
Using basic I cannot save files. I keep getting an "error 141 no channel" when I try to save.

I can INIT disks and I have been able to XFER files from drive A to B. that is about as far as I have been.
Currently I am trying to use the Gotek as drive B but all of the images I have used do not seem to work. CDOS gives seek errors 32 and 36 hex which indicate it can't find the first track or read it. here is my gotek img.cfg for single sided, single density DSK images:
[::92160]
description = double sided single density 5.25" CP/M disks
cyls = 40
heads = 1
interleave = 3
secs = 18
bps = 128

The images I am using are from the Z80 pack.

www.autometer.de/unix4fun/z80pack/ftp/cromemco/
I have tried the cdos 00205, 1075, 2585
These images are 92160 bytes in size which calculates to single sided single density.

Are there other images on this site I can try with the 4FDC controller or does someone know where there may be other images to try?

Also the following questions:
Am I using the DSK files with the Gotek right?
1) Can I use IMD files?
2) Is there an way on linux to see what the dsk files look like?(or windows if needed) I guess I assume they are raw but maybe a special signature or what format CP/M is looking for to make a disk format valid?
I guess any help with getting images working would be great.
3) Should I be using the Z80 pack and creating my disks that way?
4) Can I use CP/M-86 to make disk for the s-100 system?

Thank you everyone for all of the help.
Click to expand...
Most of the help available on the topic of using a Gotek (with Flashfloppy) on a Cromemco system that you will find on the internet has the Gotek emulating an 8" drive. There is no reason it should not also be able to emulate a SSSD 5.25" drive in a Cromemco system, but the amount of available information is more limited.

On a Gotek using Flashfloppy firmware emulating a Cromemco floppy there are two options for the format of the disk file image - either IMG (not IMD or DSK), or the raw flux recording format which is HFE. There is an "HxC Floppy Emulator" utility which can be used to convert between IMD, IMG, and HFE formats.

Disks formatted by CP/M-86 running on an IBM-PC were only readable by a very small number of S100 systems developed in the late 80s. It is not capable of creating, reading, or writing Cromemco CDOS format disks. There is an excellent MSDOS app called 22DISK that was able to read and write a hugh number of CP/M disk formats including Cromemco CDOS - but in the case of Cromemco CDOS or CP/M I believe it only supported DD disk formats.
 
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I have been working with this machine for the last few days and have learned a little more.
I have upgraded the machine so it has 64K ram and bank selection seems to work so it disables RDOS and enables the last 16K.
right now my ram is 32K static at the bottom, 16K from the measurements DMB64 card, and the last 16K is a cromemco 16KZ card.

The 4FDC card has been modified to handle newer versions of CDOS as per the instructions that Amardeep-AC9MF posted.

I have been able to boot (2) 5" disk images. CDOS 0020 and 001BASIC (also version 0020).
Other images look they want to load but are not successful and never see a prompt.
image 051C0217 will spit random text at me but no command prompt.

Running programs like INIT, EDIT, BASIC, all give me errors about jump addresses and they die so nothing is usable.
Trying to save a basic file to disk give me a error 141 NO CHANNEL.

I can access plenty of disk images from CDOS but they won't boot.
I have also found you can't boot with 0020 and try to run newer software (like CDOSGEN)
I am wondering if someone can created a CDOS2 disk with 64K ram, A,B 5" (DS/SD)and C,D 8" (SS/SD)
I have not been able to figure out how to accomplish this with only having 0020 bootable.
I have been using the HxC emulator and Z80Pack cromemcosim, but not sure if I can use that to generate my own disks.

Maybe if someone could give me some ideas on how to pursue getting CDOS 2 working on the 4FDC.
Should I be looking at versions of CP/M that might work?

Thanks for the help.
 
I am able to use the MEMTEST8 program from the CDOS C0217 image. I am testing the ram and it looks like I have some problems. it does 3 tests: Peak, Valley and Delay. If it has errors it shows which tests failed in which chip:

B.memtest8

�
�16KZ MEMORY TEST - disk version 00.08
�Commands for this test are as follows:
� CTRL-C: Boot-up CDOS using internal RDOS.
� CTRL-E: Print error history.
� CTRL-P: Print IC map of 16KZ.
� CTRL-Q: Quit to resident monitor.
� ESC: Start memory test over again.
�
�Bank: 0 Cards: 2
�
�
Only cards 0, 4, 8, and C may be selected
�
�16KZ MEMORY TEST - disk version 00.08
�Bank: 0 Cards: C
�Bank:
�
(Cromemco 16KZ board)
�(Card C) -0- -1- -2- -3- -4- -5- -6- -7-
�(Bank 0) 0: ... ... ... ... ... ... ... ...
� 1: ... ... ... ... ... PV. ... ...
� 2: ... ... ... PV. ... ... ... PV.
� 3: ... PV. ... ... ... ... ... PV.

(the upper part of the 32K static ram )
�Bank: 0 Cards: 4
�Bank:
�
�(Card 4) -0- -1- -2- -3- -4- -5- -6- -7-
�(Bank 0) 0: PV. PV. PV. PV. PV. PV. PV. PV.
� 1: PV. PV. PV. PV. PV. PV. PV. PV.
� 2: PV. PV. PV. PV. PV. PV. PV. PV.
� 3: PV. PV. PV. PV. PV. PV. PV. PV.


Does the Cromemco memtest only work with 16KZ board or will it work with the generic 32K static ram board? I imagine the image of which chips failed will be wrong but the process should still succeed if the ram is OK?


Looks like I have more work. I will test more and report back.
 
After Memory tests and replacing 5 bad chips on the 16KZ board, CDOS 2 boots...
I might be fighting memory problems, I need to check all of my ram

CROMEMCO RDOS1
;b

CDOS version 02.17
Cromemco Disk Operating System
Copyright (c) 1978, 1979 Cromemco, Inc.

A.dir
CDOSGEN COM 28K INIT COM 9K
STAT COM 8K MEMTEST8 COM 4K
DUMP COM 2K XFER COM 4K
SCANG COM 10K CDOS COM 12K
*** 8 Files, 9 Entries, 77 K Displayed, 4 K Left ***

A.stat
STAT (System Status) version 02.09

SYSTEM MEMORY: DEVICE CONFIGURATION:
Operating system version 02.17 CON: = Console 0
Total system memory 64 K PRT: = Printer 0 (PAR:)
Operating system size 11 K RDR: = Reader 0
User memory size 53 K PUN: = Punch 0

DISK MEMORY: DISK CONFIGURATION:
Disk label CDOS0217 Cluster size 1 K
Date on disk 11-24-97 Sector size 128
Total disk space 83 K Total directory entries 64
Disk space used by directory 2 K Directory entries used 10
Disk space used by files 77 K Directory entries left 54
Disk space left 4 K

DRIVE: Double sided, Dual density
DISKETTE: Single sided, Single density

A.
 
When using a Gotek/FlashFloppy, be aware that the Drive Select pins are geared up for use with an IBM PC compatible so a few adjustments may be required for your Boot ROM.
(i.e. supports IBM crossed Drive select 34 way cables)
The Gotek drive is merely a ST Flash microcontroller so you can't really go wrong with it.
It's also a good idea to upgrade it with an OLED display and rotary switch to select drive images.
 
Someone said:
When using a Gotek/FlashFloppy, be aware that the Drive Select pins are geared up for use with an IBM PC compatible so a few adjustments may be required for your Boot ROM.
(i.e. supports IBM crossed Drive select 34 way cables)
The Gotek drive is merely a ST Flash microcontroller so you can't really go wrong with it.
It's also a good idea to upgrade it with an OLED display and rotary switch to select drive images.
Click to expand...
Goteks that have already been upgraded with Flashfloppy, an OLED display, and a rotary selector switch are sold by many eBay sellers. They are well worth the small added cost over buying an unmodified Gotek and doing all the upgrades yourself.

A Gotek with Flashfloppy will have a standard Shugart interface when so specified in the FF.CFG configuration file placed on the USB stick - no need to make any modifications to the floppy controller or software. A standard 34 conductor straight through cable should be used ie not PC style with the section of flipped conductors. Most Goteks already have a jumper block to allow selection on DS0 or DS1. To address the Gotek on DS2 or DS3 a modification to the cable connection will be required - one way this can be done is with a floppy cable breakout board like eBay 126151414945.
 
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I bought my Gotek with the oled and spinner knob. Soldered headers on the back to jump the program pins. created a goofy USB cable to flash it (first time I had DATA +/- switched it will show up but not respond). then using linux I loaded flashFloppy on the Gotek.
My FF.CFG file is minimal. I downloaded Hxc emulator (used in wine, works great) and used that to load raw or IMD and create hfe files. I dropped them onto the usb stick (no folders for me) and I can boot 5" images with the 4FDC. 8" images with a 50/34 pin adapter give me drive not ready errors.
Otherwise the Gotek has been an awesome tool for getting things going.
 
I will also post my summary for my IMSAI computer with Cromemco guts. I have everything working.
My biggest problem was bad ram. Once I could get CDOS booted and could run MEMTEST I found I had tons of ram problems. After finding 5 bad chips on a 16KZ board I gave up on that and installed a PIIeon 65K board which works great, minimal config. Does bank selection with RDOS perfect.
I was also able to get the 8" shugart SA800 drives working with the 4FDC. I had to modify the floppy drive and solder a jumper to the TS (true separation) pins. I also had a drive that wasn't giving a drive ready signal because of some gummy stuff on the sector hole sensor.
I also realized that drive select 3 and 4 are not on the right pins and that was frustrating. On the 4FDC controller, pin 4 is DS3 where is should be pin 30. I jumped a wire and now DS3 works and that is where I have one 8" drive. DS4 is a little more complicated since pin32 should be DS4 but it is connected to something that is not labeled in the schematic. I will cut this trace from the pin and jump pin 18 to pin 32 so DS4 works.
I want to boot from the 8" drives (A and B). This has been tested and works fine. A Tandon-100 drive as C and the Gotek as drive D. Since the Gotek can only be selected as DS0 or DS1 I will have to make a custom cable that crosses DS4 to DS1 just for the Gotek.
My current project is finding software and converting it to the right media density. I would like wordstar, supercalc, dbase, kermit, xmode, pascal, etc but they are on double density media. I am learning how to use cpmtools and HxC emulator to pull files of the DD disks and copy them onto single density disks that the 4FDC can handle.
I also have a Tuart board, a PRI (printer board not knowing the tuart board has parallel ports) and some 16KZ ram that I would like to set up with bank selecting if CDOS will work with it. It seems CDOS will handle multiple memory banks.
I also bought a bitsaver board for programming 2708 ICs, a JAIR SBC to build and test.
I also noticed someone is selling dazzler kit boards and that would be fun to get some graphics working.

Thank you to everyone that has helped with this first part of the project. It saved alot of time having people help you along when you get stuck.
I am sure I will be posting questions about programming and CDOS on other threads.
Thanks everyone!
 
Endersending said:
Someone on Etsy is selling them
Click to expand...
I have no idea who that Etsy seller is.
My recommendation is that if you are interested in buying any of the boards described on the S100Computers.com web site, you purchase them directly from Todd Goodman who maintains almost a full stock - his list and contact information is posted here:

boardinventory [RetroBrew Computers Wiki]

www.retrobrewcomputers.org www.retrobrewcomputers.org
Not only does he sell this board for less than the one on Etsy, but he will also sell you the set of three pre-programmed CPLDs this board requires.

That being said... it has been almost 8 years since the Dazzler II board first came out and it is difficult to build because it uses several obsolete parts which are difficult to source. Most problematic are an Epson-branded oscillator with an uncommonly used frequency, and a dual-port RAM chip. If you want to build this board, before you do anything else make sure you can source all the parts.
 
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