>Tony Duell wrote:
> > Does this annoy anyone else? That the systems can't format their
> > own media, I mean :)
> Not when there are _good_ techncial reasons for it (like the fact that
> the RL01 can't format a blank pack becuase to make a positioner that
> could step accurately enough without reading servo bursts from the
> platter would be rediculously expensive).
Jerome Fine replies:
Note that the RK05 media could be formatted by the PDP-11 operating
systems. One of the "tests" I always used under RT-11 was to make a
duplicate of a pack and then run BINCOM. If there were no errors with
BINCOM, then the original media was OK. BUT, after constant use
for a month or two, I found that the system media (SY:) on the production
system would start to lose its format - for whatever reason that would
happen.
Whoever wrote BINCOM (as opposed to DUP) left out all the extra code
to read a "difficult" block the extra number of times needed if it could be
read. Thus, "COPY/DEVICE RK0: RK1:" would work (using DUP), but
not "DIFF/BIN/DEVICE RK0: RK1:" (using BINCOM). Thus it was
possible to recover "difficult" blocks before they were gone, FORMAT
the original RK0: media to whatever standard was required and copy the
duplicate data back to RK0: and continue.
Thus, I have a question to ask. What was the difference between the
RK05 that can be formatted and the RL01/RL02 which can't - other
than the method that DEC chose to lay out the servo tracks? How much
more would it have cost to allow the RL01/RL02 drives the ability to
format in the field just like the RK05?
And could the problem have been more because of the fact that
the RL01/RL02 became a "DEC owned" product just like the
attempt by DEC to pretend that all RX01/RX02/RX50 floppy
media should be purchased from DEC as well?
> But when it's done for marketing reasons (so you have to buy the
> manufacturer's expensive pre-formatted floppies, as was the case with the
> RX01, etc) then yes, of course it annoys me.
The format of the RX01 was identical to the IBM SSSD format. Thus,
other than the fact that DEC "forgot" to mention that fact and that DEC
also "forgot" to include the necessary few bits of hardware to allow the
drive to format media off-line (3rd party manufactures of look-alike
RX01 drives), many other manufactures made floppies that were
pre-formatted. However, I do seem to remember that DEC almost
always seemed to charge the highest price for "genuine pre-formatted"
RX01 media. From my point of view, it seemed to say a lot about
a company that would charge up to 10 times the cost of non-formatted
media when most other companies charged only a small (about 10%)
premium.
The RX02 media was identical to the RX01 media. Without going
into all the details, the RX02 drive could flip the density on the media,
BUT it had to be formatted FIRST. On the other hand, some media
did develop "difficult" blocks. In that case, the FORMAT command
in RT-11 could be used and the "difficult" blocks were usually, but
not always, eliminated. Again, the DEC RX02 drive and controller
could not FORMAT an RX02 from scratch, but almost every 3rd
party manufacturer made a controller/drive unit which could.
The RX50 media was almost identical - except that a few DEC systems
could format RX50 media. While DEC charged to usual (1000%) premium
for RX50 formatted media, a PC could actually do the job with a
5 1/4" HD drive.
The RX33 media could be formatted in the field. They were identical
to the format of the 1.2 MByte HD PC floppies - so DEC finally seemed
to decide that the RQDX3 should be able to format the media - when
it was no longer needed - 1.2 MByte HD PC floppies were in great
supply and DEC would have looked .... charging its usual 1000%
markup for the product.
Just in case you forgot, what might the extra cost of an RL01/RL02
drive have been that could do the FORMAT command?
Sincerely yours,
Jerome Fine
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Received on Mon May 20 2002 - 20:09:25 BST