[sebhc] USB for the H8?

Dwight K. Elvey dwight.elvey at amd.com
Fri Apr 2 13:46:56 CST 2004


>From: "Lee Hart" <leeahart at earthlink.net>
>
>Lee Hart wrote:
>>> more and more of my old 5.25" floppies are gradually dying.
>
>Dwight K. Elvey wrote:
>> That is partly why I've written the program I have. It copies
>> images of the hard sectored disk to the PC. These can then be
>> transfered to CDROMs or other storage media (preferably duplicated).
>
>Interesting. I can readily see storing the data itself on some other
>media (floppy, hard disk, CDROM, etc.). What I'm not clear on is:
>
>a. How do you insure that you have correctly READ every single sector
>   on the hard-sector disk, including normally 'hidden' data like the
>   physical order of the tracks, sectors, and sides, preamble and
>   postamble bytes, etc.

 Hi Lee
 The only interesting thing that isn't in the data fields is the
volume number. I've set it up so one can optionally override this
value from the number used by the HDOS, that is in the data fields
as well. Most times, you just use it as it comes. If some program
fiddles with these values for copy protection, my program can
be quickly enhanced to deal with this.

>
>b. How do you put this data BACK onto some other kind of media so that
>   an H89 (or H89 simulator) that may not actually have a hard-sector
>   controller, 5.25" disk drive, or physical 10-hard-sector disk can
>   use it? 

 One can strip that data out by using a program to read the directories
and reassemble the files into continuous streams ( not that hard to
do. I've done this manually a couple of times ). If the data can
be moved to some other type of media and still have meaning there
( in other words it doesn't depend on having 10 hard sectors ) there
is nothing to stop one other than a little time since the data is
there.
 I've not written a program to read files using the directory yet
because I've not had a reason to. I'm only interested in archiving
right now.
 See below for the next optional way.

>
>To put this in concrete terms: Suppose it is 20 years in the future. I
>have saved all my H17 disks on a CDROM. I want to show my grandson what
>it was like in the "good old days", and run my old bootable standalone
>HDOS "Adventure" disk.
>
>Suppose I still have my H89, and manage to fix it up and get it working
>(at least as far as the H: prompt). But all my 5.25" disks are bad or
>lost. How do I get that H17 disk image from the CDROM onto a real H17
>disk?

 Take a blank disk ( or an old one you don't care about ) place it
in the H89. Enter about 50 bytes of code for my bootstrap, using the
H89 monitor. Start that program on the H89. Start my program on
the PC and tell it to download the main program( a few seconds ).
Tell it to down load the image file that you've save years ago with
my program and in about 5 minutes, you will have a newly created disk
that matches the original. You do need a working system at both
ends and a 1-to-1 serial cable.
 Why do I keep getting the feeling that people are not reading my post?
 I'll give you the code for the PC side that can be redone on most
any system that lets you send serial data. Even the new serial-less
machines could have a USB-to-serial done. One could run it from
a terminal program but it would be difficult and clumsy. I'm not
a windows person but I'm sure someone could write this code if I
wrote a spec for it.
 I do have an alternate motive here. For those that use it, I'd like
them to send me images of their disks( not personal stuff ). I have
some things already, like LISP and a Chess program but I'd love
some other stuff. I have HDOS 2.0 and some older stuff as well.
 I do have a couple of 96 tpi disk but I've not configured my system
with a 1.2M drive to try reading them to see what is there.
Dwight

>
>Or, will I need an H89 simulator program that runs on whatever passes
>for a PC in 20 years? Can it read and boot from that H17 disk image on
>the CDROM? Does this program exist today, so I'd have a chance of
>proving to myself today that these CDROM images can actually be used
>again?

 This is not a simulator. It is just an archiving method. Anyone that
wants could write a simulator and use the images.

>
>> I've been thinking about setting up a punch to make 10 sectored
>> disk out of the pile of other floppies that I have...
>
>That is a good idea. Soft-sectored 5.25" disks are at least 100 times
>easier to get than 10-hard-sectored. I suspect that there are so many
>pieces of legacy equipment that still use them that even in 10-20 years
>these soft-sector disks will still be available. [An aside: A friend of
>mine just sold an 8" full-height floppy disk drive for $350 to a machine
>tool company that needed it to repair an ancient DEC minicomputer that
>runs a milling machine they still use]
>
>Or, if we can get a group buy of some NEW hard-sector disks; they should
>have a reasonable chance of lasting another 10-20 years.
>
>If I seem paranoid about this, it's because I recently went through a
>bit of a crisis cause by this sort of thing. TMSI sold microcontrollers
>based on the RCA 1802. This is an extremely rugged microcomputer, widely
>used in military and aerospace applications. The NASA Voyager spacecraft
>used them.
>
>Today, the Voyagers are still working, still sending data from deep
>space far beyond the orbit of Pluto. But due to budget cuts, layoffs,
>equipment failures, and other problems, JPL has thrown out, lost, or
>broken all their 1802 software development systems. Sure, they have
>backup disks; 8" floppies, written in RCA's odd format that is
>unreadable by other equipment. Sure, they wrote 1802 simulators; but
>they had no way to test them to insure that they really did work
>correctly.
>
>So, I was one of a chain of about a dozen people that pieced together a
>working RCA development system, so we could read the disks. Then write
>the simulator, and verify that it worked correctly. Then translate the
>various RCA development tools (editor, assembler, debugger, etc.) so it
>was possible to modify the Voyager code, test it, and then upload it to
>the spacecraft with confidence that it would work. It was a major effort
>that took a couple years. But the end result was to extend the useful
>life of the spacecraft, allowing it to slow down its data rates and
>conserve power to continue operation despite the staggering distances
>and various on-board system degradations and faults.
>
>It's easy to assume that:
>
>a) If it works today, it will always work.
>b) If it breaks, I will always be able to get parts for it.
>c) If I can't, it won't be hard to substitute something I can get.
>d) I'll always have the documentation.
>e) Even if I lose it, it will be on the web somewhere.
>f) Or my memory is good; I'll remember how it works.
>
>Microcomputers are turning out to be exceedingly fragile. Losing a page
>out of a book, or a piece of a photograph isn't so bad; the rest is
>still usable and you can often reconstruct the missing pieces. But if
>anything is missing or wrong with a computer, the whole system is dead.
>It can be very difficult to fix or salvage anything from them, unless an
>effort is made to preserve EVERYTHING needed to maintain them.
>-- 
>"Never doubt that a small group of committed people can change the
>world. Indeed, it's the only thing that ever has!" -- Margaret Meade
>--
>Lee A. Hart  814 8th Ave N  Sartell MN 56377  leeahart_at_earthlink.net
>
>
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>


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