CoCo Floppies: Was:These darned old computers

From: Lawrence Walker <lgwalker_at_mts.net>
Date: Wed Aug 28 17:18:40 2002

> Rumor has it that Lawrence Walker may have mentioned these words:
> > Do you mean that I could use a 3 1/2" floppy in the 502, with suitable data
> >connector of course ? That would be even cooler than a 2nd 5 1/4 !!
> > That would enable me to get into "serious" OS9 stuff. Woo-haa !!
>
> Yes, provided you don't try to interface in a HD drive (1.44Meg formatted) and
> expect it to work... in a pinch, it'll work IFF you use 720Meg floppies that
> don't have the HD hole punched in them and the floppy honors that switch (some
> don't and always assume 1.44 Meg) - the datarate is 2x on the HD floppies
> compared to the DD floppies.
>
 I'm fortunate in that I laid in a good stock of "on sale" floppies since my STs
and Amigas require them. I also have a bunch of 3 1/2" floppy drives. Other
than installing and testing them is there any way of identifying which ones are
the lower density ?

> FHL had the "eliminator" which gave the CoCo a HD compatible interface;
> [obviously] it wasn't RS-DOS compatible and was only useful under OS-9;
> otherwise there was a hack for the original WD1771-based 12-Volt eating
> controllers that would double the datarate, but this was fairly involved
> IIRC; never had one of the oldies, so I can't really say for sure...

 Who is FHL ? Are they still in existence, and with the "eliminator". The best
thing would be a SCSI interface. Did anyone ever make one for the CoCo ?

> > I just ran up and checked an old data cable for floppies. It does fit
> > the 502.
> > I'm surmising that the TEAC (FD-55BV-75-U) was a standard issue floppy
> > that R-S used so any 34pin 3 1/2 connector could be used to replace the
> > 2nd edge connector on the 502. That would also imply that I could use 2 3 1/2"
> > floppies in there if wanted. Or am I simply running away with myself. Would
> > the cartridge interface accept 3 1/2" drives ?
>
> Sure - they're electrically equivalent, and work fine (I had a DSDD 40track
> 5.25" drive and 2 DSDD 80track 3.5" floppies hooked up to my CoCo at one point
> in time). - just remember to use the correct drivers under OS-9 when you sysgen
> a new bootable floppy...
>
 How did you chain the 3rd drive ? Just with a second connector on a cable
connected to the 1st or 2nd connector on the 502 ?

> [[Sellam doesn't know what kinda fun he's missing, thinking the CoCos are
> "crap"...]] BTW, Sellam, if you want a CoCo to mess with that has just
> about any kinda video you want, just get a CoCo3. It does TV/RF; Composite &
> analog RGB which can be hooked up to the CM-8 from RS, or any Atari ST/Amiga
> monitor (with the right cable, mind you) that can sync down to NTSC levels
> (which are most all the earlier ones...)
>
 I have a CM-5 that I used on a Tandy 1000 and on something else (cant
remember what) which used the special TRS video format (RGBI ?). Never
occurred to me, DOH, that I might be able to use it on the CoCo. I also
have 2 hi-res and 2 color AtariST monitors, Commodore- 2x 1702, 3x 1802,
for most of my 8-bits and a 2002 that 1 use for my Amiga 1K and 2 K.
 It's been a while since I used my CoCos and I can't remember if I used the
CoCo 3 on anything else but a TV. Possibly a 1702 (?) What from the above
would be the best choice for a monitor, keeping in mind that it would be a bit
of a pain to split out the 13 pin Ataris ( altho I do have the p/o's). The hi-
resolution Atari, if it would work, might be interesting with OS9. Tho I
have the disks I've never used OS9 but have heard nothing but raves
about it's capabilities. I believe the manual is also on-line IIRC.

 As Sam likely found, it is confusing to switch from platform to platform
concurrently. I usually immerse myself in one for some time before
working on another. I've been in a laptop mode lately. Grid and others.
I'll have to switch to a CoCo mode to explore this further.
 Too many projects, too little time.

Thanks

Lawrence


> Laterz,
> Roger "Merch" Merchberger
>
>
> --
> Roger "Merch" Merchberger -- sysadmin, Iceberg Computers
> zmerch_at_30below.com
>
> What do you do when Life gives you lemons,
> and you don't *like* lemonade?????????????
>


lgwalker_at_mts.net
bigwalk_ca_at_yahoo.com
Received on Wed Aug 28 2002 - 17:18:40 BST