Re: floppy disk
On Thu 17 Aug 2000, Andrew MacNamara wrote:
> > Where is the split in the cable, with the twisted part?
>
> Here's the cable I used:
>
> *==========B==A========B==A
> *======X===B==A===X====B==A
> *==========B==A========B==A
>
> where:
> * is the motherboard terminator
> = is cabling
> X is a twist in the cable (what is this for anyway?)
Someone once decided that it was easier to use a twist in the cabcle
to select between the first and the second drive, instead of using
the appropriate jumper on the disk itself. The twist basically
switches around the wires for selecting first and the second drive.
Now floppy drives are always jumpered for secondary, and thus you need
at least one twist in your cable.
the problem is also that the twist isn't symmetrical, so if you
have a cable with only two connectors and a twist in the middle,
you _have_ to install the cable in a certain direction.
I have an XLT (pretty similar to the XL, only with 128bits databus
and corresponding cpus) and once wanted to replace the short floppy
cable with a spare I had lying around, because that was more
convenient with the extra scsi devices I had installed. I couldn't
get that to work... So I'm suspecting that there's something magical
about the standard floppy cable. Yours doesn't look standard.
> B is one of those older floppy adapters that are female on the cable
> side, and plug onto a section of the board itself
For 5 1/4" drives, an edge connector.
> 1) buy a new motherboard, or an add-on ISA/PCI floppy controller card
I think you can forget about buying a new motherboard, unles you
can find a surplus somewhere. They're no longer current spares.
Besides, it's probably not cost-effective anymore.
Adding another floppy controller won't work unless there's some
way of physically disabling the onboard one, else the IO addresses
etc. will conflict.
> 2) install potato from CD-ROM. The installation CD supports the XL,
> doesn't it? And can't I boot off the CD-ROM, if the ARC console sees the
> device and can boot the loader file off it, right? Is a floppy required
> for CD booting? Finally, any success/horror stories of the Alpha CD
> images?
I think I once successfully booted off a cdrom with my XLT (also ARC).
Paul Slootman
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