Use of CDROM on CP/M

[leeb]

Now that I have 'a few' small-ish IDE drives available (or soon to be),
I am thinking of moving one of the 2.5-inchers to my Model 4p, and freeing up the room taken up by the 2GB 3.5-incher in there...
Which makes me think... I SHOULD be able to put a CDROM in the slot once occupied by a SSDD 5 1/4 drive, and put the 'comparably-tiny' 2.5" drive 'piggybacked' to the end of it...

There will be little trouble connecting either the 2.5 or the CDROM, but other than testing it (with a program I got with the IDE controller), has anyone actually USED a CDROM with CP/M?

I can see the need for 'special' files for access, etc UNLESS the image can be written in a format that CP/M would accept...

???

 

[Chuck(G)]

When Microsoft had to add CD support to MD-DOS, it went through the network hooks in DOS, so that the oddball file system would be less of a hassle. Trying to implement it as a conventional storage device driver would have been, er, "interesting". The network interface/redirector essentially intercepts the system calls and just passes them along. I've done custom filesystem drivers for DOS this way.

However, CP/M has no native network interface, nor is it particularly kind to hierarchical directory structures or long file names. I think your best bet is to simulate a communications program such as an ftp client and put all your code in a standalone program. There's plenty of documentation on ATAPI devices online, as there is of the CD-ROM filesystems.

So get our your pencil and start coding!

 

[leeb]

When Microsoft had to add CD support to MD-DOS, it went through the network hooks in DOS, so that the oddball file system would be less of a hassle. Trying to implement it as a conventional storage device driver would have been, er, "interesting". The network interface/redirector essentially intercepts the system calls and just passes them along. I've done custom filesystem drivers for DOS this way.

However, CP/M has no native network interface, nor is it particularly kind to hierarchical directory structures or long file names. I think your best bet is to simulate a communications program such as an ftp client and put all your code in a standalone program. There's plenty of documentation on ATAPI devices online, as there is of the CD-ROM filesystems.

So get our your pencil and start coding!

Boy, do I feel STUPID!!
I thought I was doing good to use MT+ to write my own assembler!
I think this will (also) end up on the 'back burner' for awhile... Still got some hardware-fixin' ta do! :D

I suspected as much tho... In fact I will have to rewrite/modify the example program I was given in order to use it, as MM CP/M on the 4p doesnt leave enuf ram available... tho it would if I eliminated the IDE/HD add-on... defeating the purpose, I think!

In fact, I'm still working (piecemeal) to get the HD configuration a touch more 'automated'...
All the Montezuma HD driver/install programs are built for MFM/RLL drives and my disassembler is not quite up to snuff... yet.
(It used to be tho... had a good one built until the 'crash' of the late 80s!)

I envision some 'standalone' programs... like CDDIR, CDSTAT and CDCOPY (from, of course. working with WRITEABLE drives is LONG down the road!!) and have some procedures percolating in the nether regions of the noodle as I type! :D

 

[NobodyIsHere]

Hi! Among other examples, there are a sample CBIOS for CP/M 3.0 for the S-100 IDE board on John's website S100Computers.com. Also there is CBIOS examples for the N8VEM DiskIO board with IDE for regular LBA IDE drives and ATAPI devices. However, that's the easy part. To effectively use CD-ROMs in CP/M you'd need a ISO9960 file system interface software. Non-trivial to be sure. I am not sure such a thing could be effectively wedged into a CBIOS and still have any remaining TPA. Even an application level program would be tough but probably more practical.

Good luck! Thanks and have a nice day!

Andrew Lynch

 

[leeb]

Will hafta get a look! And build-up CP/M-3! :D