How to get a bootable CPM 3 1/2 inch disc

[dcdrac]

is it possible to get CPM to boot with a 3 1/2 inch floppy with a CPC?

[HAL6128]

I guess that the 3 1/2 disc drive is original the B:. It should be possible with an ABBA-Switch.

[Terje_Norway]

Hi,


I do presume You are talking about CPM+ (also known as CPM 3.1)


It isn't a problem to boot CPM from drive B:


However You do need a special, or modified version, of CPM.
The version that comes on the original system discs do use some system calls, and do therefore start to look for the system tracks on drive A:
That's the reason WHY You can't start CPM from a DATA formatted disc. It has to be a SYSTEM formatted disc in drive A:
You do also need to have the CPM-file present on the disc (Doesn't recall the name, but it ends with EMS (Early Morning Start)


Now to the solutions to Your problem. There are AFAIK two solutions.


1.) Get the TWO CPM ROMS and install them on a ROMBOARD or Bryce's MegaFlash. Do a fast search on the wiki and You'll find more about it.
2.) There was a listing in the Danish Amstrad Bladet (10-88). See link below :
http://www.cpcwiki.eu/index.php/File:Amstrad_Bladet8810030.jpg


This file does make a single CPM.BIN file of the CPM system file. This file can be copied to any discs, and doesn't require the start disc to be SYSTEM formatted.
You can have it on a DATA formatted disc and save 9K on Your CPM disc    It does also work on drive B:
BUT there is one minor detail You should be aware of, and that is the fact that it'll only works with the normal AMSDOS formats (Data, System and Vendor/IBM ())
You could copy the file onto a ROMDOS formatted disc (716K) and start it from there, but unfortunately You can't use it because it's not compatible with AMSDOS formats.
The solution to the last problem is simply to modify a copy of the system disc, so that it does accept an extended format. This has to made prior to using the program from Amstrad Bladet.

Info on this subject is written in the instructions that came with ROMDOS. You could perhaps find it on the wiki, if NOT I do have these instructions somewhere 


Hope this has been to some use to You.


Yours

Terje Grind
NORWAY

[zeropolis79]

In theory, if a 464 user had the 3 1/2" Drive A released by Siren Software in 1992/3 and a CP/M 2.2 or Plus disc was copied onto a 3 1/2" disc (the CPC manual does recommend making a copy), would it run?

[Terje_Norway]

Hi,


I think it would run OK as long as it's running from drive A: and You are using the AMSDOS formats   


The setup You have described would only allow You to be using CP/M 2.2
For using CP/M 3.1 (CP/M plus) You would need a CPC6128 (It do use 128K, and there was something about it using direct BIOS routines from the CPC6128).
If You wanted to use CP/M 3.1 on a 464, You would also need a 64K Memory Extension and a 6128 ROM. I'm NOT 100 % sure about this, but I think You could find more about it in ACU 3-89 in the article about upgrading a 464 to 6128.


Hope my reply was of any use for You.


Yours

Terje Grind
NORWAY

[dcdrac]

ah there is the rub I have to use IBM formats to write discs using my USB floppy drive that explains it.

[zeropolis79]

Hi,


I think it would run OK as long as it's running from drive A: and You are using the AMSDOS formats   


The setup You have described would only allow You to be using CP/M 2.2
For using CP/M 3.1 (CP/M plus) You would need a CPC6128 (It do use 128K, and there was something about it using direct BIOS routines from the CPC6128).
If You wanted to use CP/M 3.1 on a 464, You would also need a 64K Memory Extension and a 6128 ROM. I'm NOT 100 % sure about this, but I think You could find more about it in ACU 3-89 in the article about upgrading a 464 to 6128.


Hope my reply was of any use for You.


Yours

Terje Grind
NORWAY

I understand that CPM Plus is 6128... I've upgraded 464's before.. It was just a theory question I thought of as I was reading the review of said drive in AA..

Thanks.

[TFM]

X-DDOS can boot from B-drive (both CP/M versions) using the !CPM,2 command.