[comp.sys.dec] RX ****ing 50s

terry@spcvxb.spc.edu (Terry Kennedy, Operations Mgr.) (02/18/91)

In article <wV8JX4w163w@zl2tnm.gp.co.nz>, don@zl2tnm.gp.co.nz (Don Stokes) writes:
> 
> Does anyone know how format a disk to look like an RX50?  Can a PC high
> density floppy drive do it?   With DOS?

 Yes. Yes. Sort of.

 Out-of-the-[DEC]-box RX50 diskettes are a bit strange. The gaps are tight
enough that a PC's controller chip (NEC uPD765 or clone) will have some
problems. I've formatted diskettes on a PC and been able to read them in an
RX50 drive, but I wouldn't bet on it always working.

  What _does_ work is a Central Point Software COPY II PC Option Board. This
is a hardware add-on used for copying "uncopy-able" diskettes. You need to
patch the drive tables so it won't double-step the heads (since an AT-type
80-track drive must double-step to copy a 360Kb PC diskette). One you've
done that, set the Option Board up for 80 tracks, single-sided, keep track
length and go make the copies. Avoid using RX50's that say "Format Copyright
Digital Equipment Corp" as masters 8-).

  Of course, there are other options. A Rainbow can format RX50's. Several
3rd-party controllers for Q-bus do as well (the Andromeda UDC11 comes to mind).

  Probably the best solution is to upgrade the RX50 to an RX33 drive, which
gives you 3x the capacity and is user-formattable. Some PDP-11 operating sys-
tems (like RSTS/E) allow formatting the disks without needing diagnostics.
[Guess where the RSTS/E group got that idea... 8-]

	Terry Kennedy		Operations Manager, Academic Computing
	terry@spcvxa.bitnet	St. Peter's College, US
	terry@spcvxa.spc.edu	(201) 915-9381

don@zl2tnm.gp.co.nz (Don Stokes) (02/19/91)

Does anyone know how format a disk to look like an RX50?  Can a PC high
density floppy drive do it?   With DOS?

The things are 80 track, ten sectors, single sided.  MSDOS 3.3 gives up
at 9 sectors.  Mumble.

At NZ$80 a box, after discounting, pre-formatted RX50s are *way* too
expensive for home use!, and I need quite a lot of them.  8-(

 
Don Stokes, ZL2TNM  /  /                             don@zl2tnm.gp.co.nz (home)
Systems Programmer /GP/ GP PRINT LIMITED  Wellington,       don@gp.co.nz (work)
__________________/  / ----------------   New_Zealand__________________________

jdudeck@polyslo.CalPoly.EDU (John R. Dudeck) (02/19/91)

There is a product that will format RX50's on an AT.  I have used it 
to format hundreds of ordinary cheap $.24 DSDD floppies, with zero
problems. 

The prodect is called Uniform-PC, and the vendor is Micro Solutions, Inc.
in KeKalb, Illinois.  I don't have the full address or phone number.

Maybe someone else knows how to contact them.

BTW I am working on a program to read RT11 files on an AT.

-- 
John Dudeck                                        "Communication systems are
jdudeck@Polyslo.CalPoly.Edu                              inherently complex".
ESL: 62013975 Tel: 805-545-9549                                 -- Ron Oliver

gpwrdcs@gp.co.nz (02/19/91)

In article <1991Feb18.090824.1117@spcvxb.spc.edu>, terry@spcvxb.spc.edu (Terry Kennedy, Operations Mgr.) writes:
> In article <wV8JX4w163w@zl2tnm.gp.co.nz>, don@zl2tnm.gp.co.nz (Don Stokes) writes:
>> 
>> Does anyone know how format a disk to look like an RX50?  Can a PC high
>> density floppy drive do it?   With DOS?
> 
>  Out-of-the-[DEC]-box RX50 diskettes are a bit strange. The gaps are tight
> enough that a PC's controller chip (NEC uPD765 or clone) will have some
> problems. I've formatted diskettes on a PC and been able to read them in an
> RX50 drive, but I wouldn't bet on it always working.

The RX50 seems to manage to read pretty much anything as long as it fits 
within its specs.  That's not what I'm trying to achieve.  I want the 
disks to *be* RX50s, not just readable, but writable, INITable etc on DEC 
systems, notably PDP-11s running RSX and VAXes running VMS, neither of 
which are terribly keen on anything that doesn't have 80 tracks at 10 
sectors per track.

>   What _does_ work is a Central Point Software COPY II PC Option Board. 
> 
>   Of course, there are other options. A Rainbow can format RX50's. 
> 
>   Probably the best solution is to upgrade the RX50 to an RX33 drive, 

Useful suggestions, 'cept that avoiding spending money is whole object of 
this exercise......

> gives you 3x the capacity and is user-formattable. Some PDP-11 operating sys-
> tems (like RSTS/E) allow formatting the disks without needing diagnostics.
> [Guess where the RSTS/E group got that idea... 8-]

I wonder if Micro/RSX has this option...  (Unfortunately, I have only 
Micro/RSX V1.0, which doesn't have much of anything -- V4.something is on 
its way.......)

However, for the time being the problem is solved, in true GP fashion, 
with some esoteric hardware -- in this case a multi-format disk 
reader/writer that just happens to have a "PDP11 RT11 RX50" option under 
"FORMAT DISK".... (I know, I should have tried that first!).  Stick a 
double density disk (High density does *not* work) into the drive, press 
the button, and Hey Presto!, one RX50.  I'm now going to round up all the 
double density disks I can get my grubby paws on (we use mainly high 
density for PCs, so DD disks are mostly rubbish) and make them into 
RX50s.

Now, where cane I get the little "digital RX50K" stickers that hide just 
inside the envelope?  8-)


Don Stokes, ZL2TNM  /  /                             don@zl2tnm.gp.co.nz (home)
Systems Programmer /GP/ GP PRINT LIMITED  Wellington,       don@gp.co.nz (work)
__________________/  / ----------------   New_Zealand_____________+64_4_737_320
     Experience is something you don't get until just after you need it.