🚀 go-pugleaf

In article <BARRY.92Aug2075341@chezmoto.ai.mit.edu> barry@chezmoto.ai.mit.edu (Barry Kort) writes:
>I use the RX50DRVR on my AT which allows my 1.2 MB drive to read RX50
>diskettes.  What this does is to create a new driveletter (F:) which
>spins the HD drive as if it were an RX50 drive.  

RX50DRVR, like RAINDOS, creates a new logical drive past your last existent
drive, so it's F: for you because you apparently have an A: through E: before
the driver gets loaded in CONFIG.SYS.

>
>RX50DRVR does not know anything about the directory structure on 
>the disks.  If I do 'dir F:' it assumes DOS directory structure,
>which works fine on Rainbow diskettes, since they use the DOS
>directory structure.

That's not quite true, since the disk organization has to be DOS as implemented
on DECmate II MSDOS/Rainbow MS-DOS only.  It is true only in the sense that
you can make your own BIOS calls to read the disks yourself without caring
about the significence.  But that's no different from doing so with any
floppy on a PC.

>
>To read RT11 formatted diskettes, there is a utility called RT11
>which groks the RT11 file structure.  I have not yet found a similar
>utility which handles the RMS-11 file structure of the PRO 3xx series.

Where can I get this RT11 utility?  It sounds useful.  Does it specifically
require/recognize the RX50DRVR or does it merely work in an innocuous way
with the same drive letter?  (Would it work also with A:? or must it have
RX50DRVR present.  If so, would it work with RAINDOS as an alternative?)

>
>I can use Norton Utilities with RX50DRVR to examine the RX50 diskette
>in the F: drive, but then I am accessing the diskette sector by sector,
>not by logical file.
>
>I haven't explored the new utilities from the gentlemen in the Former
>Soviet Union who have announced some DOS environment tools for
>manipulating RX50 diskettes.

Re the Soviet-originating files:

The files come with a piece of shareware originating in Italy that intercepts
DOS's calls for formatting commands, so that "odd" sizes, such as using:
FORMAT A: /T:80 /N:10 are now legal.  The result is a double-sided disk that
is quite suitably low-level formatted for RX50, but the high-level is PC
compatible, *not* DECmate/Rainbow's idea of MS-DOS, and specifically must be
used on a "normal" drive and *not* with RX50DRVR.  All media indicators are
stock PC-type, not RX50.  However, since the low-level is now correct, and
errors are recorded in a way that FORMAT indicated when it finished, and can
be re-confirmed with CHKDSK, etc., the media can be determined to be error-
free hopefully.  If so, then the companion program RX50INIT that comes with
RX50DRVR can be used to initialize the directory so DECmate/Rainbow MS-DOS
likes the disk, and of course the RX50DRVR-controlled logical device such as
F: in your example.  Note also that RX50INIT can be used with RAINDOS as well.
Also, RX50INIT requires ANSI.SYS be loaded purely for cosmetic reasons.
RX50DRVR and RX50INIT were designed for DOS 3.3 usage.  They don't support the
extensions to DOS brought into versions 4 and 5, so there are some problems.
RX50INIT fails totally in those two systems, and CHKDSK can't work there
either.  With some adjustment to the BUFFERS= statement in CONFIG.SYS, they
can be made to work for read/write purposes under DOS 4 or 5.  


When used with DR-DOS 6.0, all RX50DRVR and RX50INIT functions work fine.


>
>Using RX50DRVR in combination with the RT11 utility program, I can
>low-level format a blank HD diskette as an RX50 diskette, then
>put it in the PRO and do a high-level RMS-11 style Initialization.
>This allows me to create new RX50 diskettes out of plain old unformatted
>or recycled 1.2 MB HD diskettes.

Just a word about using HD media:

You can't reliably use HD media on an actual RX50, because the coercivity
is too far off in HD media.  It was designed for the higher-frequency
recording of the "real" 1.2 Meg format (500 KHz) and not the 250 KHz recording
rate of the RX50, which is actually the same as good 'ol DS/DD media (360K
kid of media).  Some revisions of RX50 drive in comination with certain RX
controllers in some DEC machins fare better than others, but it can be
demonstrated that a lot of combinations don't particularly "like" HD
media.

The designated media for RX50 is Maxell MD1DD-RX50 or equivalent, which is
what used to be called "quad" media.  This is well-honed low-density media,
so it is rated for use on 96 TPI (80 track) drives, not just 48 TPI (40 track)
drives as is usual.  Note that MD2D is not MD2DD.  (The 2 just means two-sided
which for all intents and purposes today can be ignored; virtuall *all* media
is actually made double-sided :-).)  The DD means 80-track support, but since
most media are made well-honed, most cheap disks can support 80 tracks anyway.
These disks will *not* cause I/O errors on any RX50!  However, long-term usage
requires the hub rings be removed completely (use alcohol to get the sticky
stuff off, or ask your supplier for no-hub disks!).  Failing to remove
hub rings means eventually the disks will get unreliable sooner than they
ought to due to registration problems.  All 96 TPI disks have this problem.
Note that MD2HD and MD1DD don't have hub rings!  It is rumored that there is
a "premium" line of diskettes from Fuji apart from their standard line of
inexpensive diskettes that has a specially reinforced hub area, that isn't
a hub ring per se.  If the same mechanism is used in both HD and DD media, 
then the DD type would be the best thing today to use with impunity for
RX50.  Clearly the MD1DD or MD2DD or MD1DD or the 3M equivalents are too
expensive, considering that what we want are the cheapest types of diskettes
with the hub rings never added.  (We don't want to pay more for less!)

Re RT-11 utility:

I don't know anything about the RT11 utility program, but RX50DRVR cannot
format disks; the code lacks support for the FORMAT command, and also some
calls needed by both CHKDSK and FORMAT.  Attempts to use either on DOS 4
or 5 will get error messages.  Even on 3.3, where CHKDSK is more "forgiving"
you still get the message about "format not supported on device" when
using RX50DRVR.  So, if your claim for formatting is true, the RT11 utility
must contain low-level formatting code of its own, and perhaps only needs
RX50DRVR to locate the proper device?

RAINDOS is a share-ware mostly superset of RX50DRVR, and it totally supports
CHKDSK and FORMAT in DOS 4 and 5.  It works fine with RX50INIT (assuming that
RX50INIT can work!) and suffers from only two known problems:

1)	Should you specify a format command with the FORMAT F: command,
and the O/S is DR-DOS 6, then if it really does attempt a low-level format,
it gets a cryptic error message and fails.  Note that MS-DOS 5 and DR-DOS 6
will always attempt a "quick" format if possible, unless over-ridden.  This
case of a quick format doesn't fail, but also isn't formatting!  Just 
rewriting a cleaned-up high-level format directory initialize.

2)	It is sometimes strangely slow, as compared to RX50DRVR where both
could work.  When using Norton 4.5's DT program, RX50DRVR handles the
disk at normal speed, and allows DT to mark bad clusters (if any) quite
nicely.  When RAINDOS is used, it causes many recalibrates for unknown
reasons.  In some cases, the sloth isn't that noticeable, but this is a
sore point usage.

Otherwise, RAINDOS is a total replacement for RX50DRVR, or so it would seem.
Norton NU treats RX50DRVR diskettes and RAINDOS diskettes equally since it
does one-sector I/O.

>
>Using Venix on the PRO, I can do a raw image copy of a diskette in one 
>drive to a blank diskette in another drive.  (This kind of copy will fail
>if the target diskette has any bad sectors, since there is no attempt
>to rearrange sectors to detour around any bad blocks.)
>
>Finally, by hooking up the PRO to a Unix or DOS machine via the
>COM port (or to a Unix host via Ethernet/DECnet if you have a DECNA
>card), you can transfer files via any number of techniques, ranging
>from straight ASCII upload/capture using ordinary terminal emulators,
>Kermit file transfers if you have Kermit on both machines, or by
>DECnet file transfer using NFT or dcp utilities.
>
>None of this is particularly trivial to implement, but the bottom
>line is that there are many ways to pull files off RX50 diskettes
>and transfer them to Unix or DOS machines.
>
>Barry Kort

If the Soviet files prove to work, and apparently requiring the Italian
TSR shareware program, we can probably make Files-11 RX50 diskettes as well.
I have just received these programs and will be evaluating them when feasible.
I am still working with the accompanying Italian shareware which has some
interesting "generic" features of its own with respect to the entire RX50
issue.  I suspect that its presence enhances any of these utilities, although
it's possible redundant and perhaps extraneous to some of the utilities.

In any case, there are many ways to get files moved around.

Another excellent package is 22DISK from Sydex, the same shareware author
as RAINDOS.  This package low-level formats RX50's in either DECmate CP/M-80
or Rainbow CP/M-80/86 format.  (They are similar, but not identical, although
they can read each other's disks no sweat; it's a matter of interleave, etc.
and a throughput issue, not a format per se issue.)  It then high-level
formats the disks for CP/M usage.  So, its a good place to do the low-level
formatting required for all of these other utilities.  For example, on
DR-DOS 6, you first run 22DISK to format the disk, then use RX50INIT to get
an RX50 MS-DOS DECmate/Rainbow high-level structure, and then can use
RAINDOS to transfer files, run CHKDSK, and do quick-formats with FORMAT /Q,
etc.  Notice this avoids all of the Raindos/DR-DOS interaction :-).

22DISK can get directory listings of CP/M disks, and can transfer files
to/from MS-DOS from/to the designated CP/M diskette.  It supports literally
hundreds of CP/M formats, which implies many low and high-level support
variants.  This program is highly reminiscent of the former Rainbow, and
later PC-based "Media Master" program, but is for PC/MS-DOS only, and
requires HD drives for the RX50 formats.

I believe there is an obscure PRO option for a CP/M-80 board, so this might
be yet another way to get files in/out of a PRO.

So, like cats, there are many ways to "skin" an RX50 :-).

cjl