Re: versioned filesystems in linux (was Re: kernel support for

[John Bradford <john@grabjohn.com>]

> > Just wondering how difficult it would be to make a 9-track tape drive
> > from scratch, and connect it up to the parallel port...  Do you think
> > that old hard disk motors, from 5.25" MFM disks be powerful enough for
> > the 120IPS tape transport?
> 
> The disk-drive motors, even for the 5.25 floppies were pancake motors
> designed to directly turn the floppy, or run a belt with a small
> ratio. You need a motor that runs at relatively high speed to turn the
> capstan. If the capstan was 1 inch in circumference (about 0.2'' in
> diameter), you need 120 revs/sec = 7200 r.p.m.  You won't do this with
> a floppy motor.

I was thinking of hard disk motors...  Actually, some of those would
be 3600 r.p.m., so if we used a large capstan, we might be in with a
chance :-).  (You'd really need to drive the actual reels as well,
though, I can't see us starting and stopping the whole thing very
quickly just using the capstan motor.)

John.