Monday, November 07, 2016

Homage to the Floppy

In the last 2 months Marcus has been extremely busy, polishing, checking, filing, refiling and compacting his floppy disk collection. 

But Why Then?
Here are the cleanup objectives/ thoughts

- Space compacting:   We might have to move soon.  Maybe internationally pan-galactically.  Smaller stuff and less of it. Important.

- How much redundancy do we need.  Physical and Physical Copy and how many digital copies?  If we can easy re-create physicals from Digital images, may there is a case for just keeping digitals and a stack of blanks  (I mean what could possibly go wrong there!)

- What machines still actually have floppy drives.  And which emulators.  And what machines can actually digitise or produce physicals>

- Do all your floppy drives still work.  Time to test them, and for reasons of space saving, ditch the broken ones.

- What modern OS are still actually supporting Floppies.  While back I found that 64 bit Windows Server did not fully support  (what it did do was annoying pulse the floppy drive, and seek home the drive every few minutes!)

 Under Cromix 172 XXU formatting of a Physical 8" drive appears to work.  (It's a 3.5 Japanese format drive emulating a 8" of course

 But in fact trying to read the floppy shows it does not work

Now removing the CPU card and inserting a 68010 one and running the 68010 version of the OS Cromix 167 level:

Same physical floppy can be mounted and have files copied to

So it's a Cromix 172 XXU bug I believe

If you own a HxC floppy emulator you can use the 32 bit Windows PC Gui program to look at Dave Dunfield .IMD images and convert to and from them to .HXC format

 More hours of floppy drive testing.   Here are the Japanese format capable 3.5 inch drives that I covert to 8" emulators.   They are able to do the critical 360 rpm and 500 MFM density format and use a standard 1.44MB floppy which you can still buy new if you search hard enough.

I should mention that all my Vintage computers use 12V and 5V power from additional PC power supplies.  This way any current overloads from those spinning disks or diskette drives won't blow up a vintage power supply it might be otherwise impossible to replace.

Here I show you the standard way to close the power switch connection on the main PC supply header that would normally go to the motherboard and power switch.  So the PSU will then simply power on when you have the mains lead in.

Yes you can really boot Cromix, the last and fastest 68020 version from a single floppy.  A 1.2MB one.  As above physical floppies don't work picture shows this B diskette i.e. fdb in Cromemco Cromix terms is from a HxC emulator.

The HxC floppy emulator display can be seen at the front on the left

This is an intermittently failing cheapo crappy Power Supply that caused me to have kittens.   It was powering the 5V and 12V rails in the above Cromemco Computer.    Initially I blamed possible shorts in my floppy conversion or Hard Drive load issue.  Instead it was this blasted PSU.   I had to buy a new BeQuiet PSU to replace.  More expenditure

An extract from a Cromemco manual trying to tell you how to wire the 2 pin priority interrupt cable. What it doesn't exactly stress quite enough is:  Viewing each S100 card the IN and OUT pins are he same on all cards.  Except the Floppy Disk controllers.  Yes, just to keep you on your toes.  For the Cromemco 16 and 64FDC the pins are reversed.

The infamous decision by Cromemco to always write the first track of a floppy in Single Density (SD) so that old disk SD only controllers like the 4FDC could read any disk, and if the diskette label label on track 00 said characters 'DD' for double density then it could throw up a helpful "can't read Double Density Diskettes".  Unfortunately, years later, this decision leads to any Double Density format diskette being almost impossible to copy and duplicate because the first track is in SD Single Density.  Well actually worse, the first side of the first cylinder  (where a cylinder is both sides of a track). So if your imaging format does not cater for fixed densities you are basically screwed.

I have this wonderfully fancy combo 5.25 and 3.5 inch Teac drive but can I understand the instructions.  NO!

Setting the BIOS on my Dual Xeon Processor, 2005 ish, still quite powerful Motherboard to try and read Japanese i.e. 8" format diskettes in physical 3.5". That is to say the Cromemco diskette collection. But did I get anywhere, even after hours of effort? ... No!

 Another fancy thing:  The combo card reader (via USB) and 3.5" floppy (ribbon cable to Floppy port, i.e. its not USB).  Still moderately available second hand on ebay

The moment when after hours of nothing working you realise there is another option in the BIOS that switches on the Floppy controller. Something I normally turn off if there is no Drive, just to make the computer that much simpler and maybe faster.

Here is the motherboard.  Disassembled again.  I'm reusing the case for the new workstation.  Now that IS economy,  though if I want to restart this board swapping this E-ATX board is non trivial I can tell you.

 Behind the scenes fiddling until at last success!

No really it is working under a DOS window with Windows 2016 Server.

 I did some Centos 7 testing to check that the floppy drive would work there.  I always use rufus to make the bootable USB key to save making a physical DVD

 More testing.  This time with PCLinuxOS.  I can confirm that this distribution also handles floppy disks.

 My single point of failure but still running, lifesaver IBM PC XT 286.  Mine since new :-) Equipped with a pseudo 8" drive in the form of a 3.5" diskette and a Hard Disk controller with CF slots so I can pull out the card and sneakernet it to my other computers to upload to the website.

 Only 1 floppy is left alive on the Cromemco CS250.  You can just squeeze a bootable OS onto the 360K physical floppy and I mean just.  You have to do all sort of tricks like reduce the inode count to give you those few extra necessar Kilobytes.

 The main flexible Cromemco that has from left to right:  HxC floppy emulator.  It can emulate two drives concurrently  A and C drive.  Clearly CDOS knows about A: and C:, but Cromix would see them as /dev/fda and /dev/fdc, or if you reconfigure, because HxC is that clever /dev/sfda, /dev/sfdc or even /dev/ufda and /dev/ufdc.  To the right a physical 360K drive and lastly a B: taking physical 3.5" diskettes written to be 8".  That is to say 77 tracks, usually Double Density format  (excluding track0side0!!),  2 sides.

After weeks of reading, checking, sealing, some painful discarding. The 5.25" physical collection is reduced to a single IKEA box. These diskettes are upto 40 years old now.

Now mostly hermetically sealed, compactly stored, and all digitally imaged, I need the collection to last for another 50 years.  And I think it will.  With the likes of the HxC emulator it will be usually virtualised floppies in the future.  Physical Floppies.  I will miss you

Stones: Miss You