3B2 memory, floppy drive

Paul R Hoffman hoffman at wrdso.ATT.DSO
Thu Jan 18 14:55:30 AEST 1990


In article <11033 at attcan.UUCP>, ram at attcan.UUCP (Richard Meesters) writes:
> In article <860 at red12.qtp.ufl.edu>, taylor at qtp.ufl.edu (Charles Taylor)writes:
> > For anyone with 3b2/300 experience....
> >   1. Is the floppy drive that came standard on the machine a 360K or
> >      1.2 Mbyte floppy drive and which device do I use to address it
> >      as a 1.2 Mbyte drive? (if applicable).
> The 3B2 line uses a 720K floppy drive, You must use 96tpi double or high
> density diskettes with this drive, and you are better off if you use the 
> high density media ( more reliability ).
..............................^
  Sorry, I disagree.  A few years back you could purchase diskettes known
as "QUAD Density": These worked the best.  But I have had good success using
name brand DSDD (double sided double density) diskettes, and have had POOR
success using DSHD (double sided high density) diskettes. I could go into my
theories as to why, but I'm not a hardware engineer so will let my experiences
explain themselves.
> ------------------------------------------------------------------------------
>      Richard A Meesters                |
>      Technical Support Specialist      |     Insert std.logo here
>      AT&T Canada                       |
>      ATTMAIL: ....attmail!rmeesters    |      to mind...clean up your act"
>      UUCP:  ...att!attcan!ram          |
> ------------------------------------------------------------------------------

  I had bad luck using DSHD floppies on the 3B2 drives.  They would appear to 
work, but I had a high failure rate reading the same floppies later.
(Stored properly, not near magnetic fields, etc.)
  On the other hand I have had very good luck with plain old DSDD floppies.
I've worked as a tech on these machines, been tier 2 support on applications
running on this hardware, etc.  I've also reloaded selected file backups on
DSDD flops after upgrades between (orig Sys V Releases -> 2.0 -> 2.04 -> 2.0.5 
-> 3.0 -> 3.1 -> 3.2)  Add in a hard disk crash, as well as some other reloads
due to experimentation, and I probably have backed up and reloaded many more
diskettes on these floppy drives than most.  Everything else Richard had in
his reply regarding memory boards, system response, etc. goes along with my
experience on these boxes over the last 6 years.
  ALSO, there is an outside vendor who sells a software package for the 3B2
to allow the reading, formatting, and writing of 360K MS-DOS diskettes.  They
have a bracket which expands the 2 memory slots to 3 as well, so you can add a
third memory board. I have no experience  with this board, as it potentially
have affected the maintenance agreement I have on the box. If you are busy 
enough to be swapping (or paging & swapping) in the 4 MB configuration, you 
probably need a box with more horsepower than your 3B2/310.

Paul Hoffman,	ATT Technical Support Staff, System Administrator on 3B's
-- 
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Paul Russell Hoffman	UUCP/Email:  att!fswest!hoffman or  attmail!phoffman
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