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deramp5113
August 5th, 2015, 09:04 AM
As discussed in several threads recently, hard sector 5.25" disks - especially the ten sector disks for North Star controllers - are getting very hard to find.

I now have a working prototype of a virtual sector generator that connects onto the 34 pin ribbon cable (in-line or just an extra socket pressed onto the drive cable) that makes soft sector floppies look exactly like hard sector floppies to the controller. The board syncs to the rotational rate of the currently selected drive and generates sector pulses to the controller so the controller can't tell the difference. It has been working very reliably, even with the older, full-height, belt-driven drives. The board requires no external power connections and is very unobtrusive - barely wider than the drive cable.

For example, with the board clamped onto the drive cable, an original North Star system with original drives can work transparently with hard or soft sectored disks.

I'm going to finalize the layout and run a panel of the boards. I'll probably get 20 or so boards off the panel for those who are interested.

Mike

Nama
August 5th, 2015, 11:36 AM
Hi Mike,
This sounds great,
Please count me in for one unit, and depending on the price I may get two.

Thanks

new_castle_j
August 5th, 2015, 01:28 PM
Awesome, I will need one too!

jgalinat
August 5th, 2015, 01:57 PM
Hi Mike,
I would love to have one. Please put me down for one. That way I could recreate my first system, an IMSAI with a Northstar Floppy Controller. The thing holding me back was the non-availability of the media. This would obviously solve that.
Jeff Galinat (proud owner of an Altair clone)

griffk
August 5th, 2015, 03:55 PM
Neat!

Pls put me down for 1 or 2

thx

gwk

Chuckster_in_Jax
August 5th, 2015, 08:06 PM
I'm interested in one also!

pbirkel@gmail.com
August 5th, 2015, 10:31 PM
Hi Mike,
I would love to have one. Please put me down for one. That way I could recreate my first system, an IMSAI with a Northstar Floppy Controller. The thing holding me back was the non-availability of the media. This would obviously solve that.
Jeff Galinat (proud owner of an Altair clone)

Similar reasons here, so sign me up for one, please Mike. I'd be much obliged!

Corey986
August 6th, 2015, 02:35 AM
I'll take two also!!!

Now if you can only make one for 8" drives also :-)

smp
August 6th, 2015, 02:58 AM
Hi Mike,

Thanks for another awesomely useful product!

Yes, please put my name on your list for one.

smp

deramp5113
August 6th, 2015, 06:16 AM
Now if you can only make one for 8" drives also :-)

I actually developed the techniques for making this work reliably while developing soft-sector media support for 8" drives in the Altair FDC+. Unfortunately, the data layout Altair used on their 8" floppy is so tight that soft-sector media just won't work reliably with belt driven drives. However, soft sector media is reliable when used in drives with direct drive hubs like the Pertec FD-400 (typically found in the Altair floppy cabinets) and later half-height 8" drives like the Shugart 810-860 series.

In contrast, the data layouts used on the 5.25" hard sector formats are much more forgiving (about three times as much timing slop allowed), so even belt driven drives seem to work fine with soft sectored media.

I'm not familiar with 8" hard sector formats other than the Altair format. It could be that some other 8" hard sector format allowed more timing slop than the Altair format. If so, these may work fine with belt driven drives and soft sectored media.

Finally, the "rarity ratio" of hard-sector vs soft-sector 8" media isn't nearly as lopsided as it is for 5.25" media. Both media types are almost equally as hard to find in the 8" format, so soft sector media support isn't as big an advantage as it is for the 5.25" drives.

Mike

CommodoreKid
August 6th, 2015, 06:47 PM
Out of curiosity, how many components populate this board?

Additionally, any reason that one of these wouldn't work with the hard sectored controller on a Heathkit H89? I realize that it's not an S-100 system, but it isn't all that far off the mark.

This device sounds fascinating nonetheless! I would love to see pictures of the prototypes, if you have 'em.

smp
August 7th, 2015, 03:59 AM
Additionally, any reason that one of these wouldn't work with the hard sectored controller on a Heathkit H89? I realize that it's not an S-100 system, but it isn't all that far off the mark.


From the way Mike described it, I see no reason that this cannot work with the Heathkit H8 and H89.

smp

Chuckster_in_Jax
August 7th, 2015, 06:18 AM
Additionally, any reason that one of these wouldn't work with the hard sectored controller on a Heathkit H89?

A visit to the SEBHC website shows there is already an adapter that works with the H\Z89.

http://sebhc.lesbird.com/storage/storage.html#HARD_SECTOR_FLOPPY_EMULATOR

deramp5113
August 7th, 2015, 06:49 AM
Out of curiosity, how many components populate this board?

Additionally, any reason that one of these wouldn't work with the hard sectored controller on a Heathkit H89? I realize that it's not an S-100 system, but it isn't all that far off the mark.

The board requires just a processor, a transistor, and some diodes and resistors for signal protection.

While I'm not completely familiar with the Heathkit computers, based on the fact that the Heathkit data layout is very similar to the North Star layout, and therefore does not require tighter timing tolerances, this board should work fine with the Heathkit computers.

Mike

deramp5113
August 7th, 2015, 07:04 AM
A visit to the SEBHC website shows there is already an adapter that works with the H\Z89.

http://sebhc.lesbird.com/storage/storage.html#HARD_SECTOR_FLOPPY_EMULATOR

Chris did a great job designing the HSFE. In fact, speaking with Chris a while back about the HSFE is what made me add soft sector media support to the Altair FDC+. In the end, Chris was only able to get the HSFE to work reliably with newer 3.5" drives which have a very accurate and steady rotational rate compared to older 5.25" drives.

The primary difference between this newer board and the HSFE is ability to work reliably with the 5.25" drives that are part of the original systems. It does this by syncing to the rotational rate of the current drive and using 24-bit math to prevent cumulative rounding errors when computing each sequential sector time.

I also plan on having a 10/16 sector jumper on the board so it can also be used with 16 hard sector systems like the Altair Minidisk, Micropolis floppy subsystems, and Vector Graphic Micropolis and Tandon configurations.

Finally, I want the new board to not require an external power source. I can achieve this by harvesting power off a few key signals on the ribbon cable. This works great with a typical North Star with Shugart SA-400 configuration. Unfortunately, when different controllers and floppy drives are thrown into the mix, the power-harvesting idea runs into a few hitches - primarily due to different signal terminators (150 ohm pull-up vs 220/330 pull-up/down vs 1K pull-up). At this point, I'm not sure if I'll give up on the no-power idea and build a 9v battery holder onto the back of the board or not.

Mike

litterbox99
August 7th, 2015, 07:22 PM
I would be interested in one board.

I have an Imsai with a NorthStar controller and two iffy SA400 drives.

Drive X only boots/reads certain floppy's , and
Drive Y reads the rest of the floppies...

I want to archive what I have and use modern drives.

Will your product co-exist with a working SA400 ?

I want to strap up a SA400 & your drive converter
to another floppy at the same time so I can archive
off the old media.

What Drives have you tested this with ?.

I do have 20 new hard sectored floppys from Athna,
but I'd rather use a reliable drive that's in alignment.

Todd

deramp5113
August 8th, 2015, 05:22 AM
The board is on the drive cable that is common to all drives, so any drive on the cable can be hard or soft at any time.

I have tested with the Shugart SA-400, Tandon TM-100, Micropolis 1015, and Teac 55-GFR. Only the TEAC is a newer direct drive hub. The others are belt driven.

Mike

MarsMan2020
August 8th, 2015, 05:09 PM
Mike - I'd like 2 boards. Finally got my hands on a Mindless Terminal to go with that MZ you helped me get up and running - it'd be great to be able to use soft sector disks!

deramp5113
August 9th, 2015, 04:43 AM
Quick poll,

How many would like to build the board themselves: I provide the board, a programmed processor, and a parts list at Digi-Key. The board would be slightly larger to accommodate thru-hole parts.

Or, the board is completely assembled, tested, and ready to go, a bit smaller, but of course, more expensive.

Mike

griffk
August 9th, 2015, 05:02 AM
Quick poll,

How many would like to build the board themselves: I provide the board, a programmed processor, and a parts list at Digi-Key. The board would be slightly larger to accommodate thru-hole parts.

Or, the board is completely assembled, tested, and ready to go, a bit smaller, but of course, more expensive.

Mike

I say we build them ourselves!

thanks
gwk

smp
August 9th, 2015, 07:51 AM
Quick poll,

How many would like to build the board themselves: I provide the board, a programmed processor, and a parts list at Digi-Key. The board would be slightly larger to accommodate thru-hole parts.

Or, the board is completely assembled, tested, and ready to go, a bit smaller, but of course, more expensive.

Mike

Assembled and tested for me, please!

smp

new_castle_j
August 9th, 2015, 08:15 AM
Assembled and tested for me, please!

smp

Me too, pre-assembled

Chuckster_in_Jax
August 9th, 2015, 08:22 AM
Quick poll,

How many would like to build the board themselves: I provide the board, a programmed processor, and a parts list at Digi-Key. The board would be slightly larger to accommodate thru-hole parts.

Or, the board is completely assembled, tested, and ready to go, a bit smaller, but of course, more expensive.

Mike

I can build the board myself.

BTW, put me down for a second board.

Chuck

MarsMan2020
August 9th, 2015, 02:26 PM
Quick poll,

How many would like to build the board themselves: I provide the board, a programmed processor, and a parts list at Digi-Key. The board would be slightly larger to accommodate thru-hole parts.

Or, the board is completely assembled, tested, and ready to go, a bit smaller, but of course, more expensive.

Mike

I vote for built-it-myself, I've built several of the N8VEM SBCs so a floppy adapter shouldn't be a big deal.

Will the board be able to interface to the floppy systems that use a card-edge connection instead of pins like the Micropolis drives in a Vector MZ?

jgalinat
August 9th, 2015, 05:35 PM
Hi Mike,
I vote for the bare board with processor and a list of parts. I like to build stuff & have a well stocked parts cabinet. Thanks for considering it as an option.
Jeff

deramp5113
August 10th, 2015, 06:28 AM
The board has two 34 pin headers on it for use with IDC sockets. The board can be in-line (i.e., cable from FDC to board, cable from board to floppies), or "T" connected to the existing cable (i.e., original cable from FDC to floppies with and IDC socket pressed onto the cable somewhere along its length; this single socket connects into the board).

Mike

KC9UDX
August 10th, 2015, 06:41 AM
I'd hate to have to open and reseal large quantities of floppy disks, but I wonder how hard it would be to build a punch to convert disks to hard-sector.

Actually, come to think of it, a single punch could be fitted into a modified floppy drive, so it wouldn't be necessary to open the disk. That sure would be a fun project if I had the time.

Roman
August 11th, 2015, 08:33 AM
I am interested in one board too (bare board or assmbled).
Roman

deramp5113
August 11th, 2015, 12:11 PM
Is most everyone planning on using this for North Star controllers? How many need it for a Micropolis floppy controller?

The details are long and boring, but the Micropolis controller presents a problem in one particular corner-case related to drive selection that may not be solvable with the board itself.

Mike

smp
August 11th, 2015, 02:25 PM
Is most everyone planning on using this for North Star controllers? How many need it for a Micropolis floppy controller?


Yes, I have both a single and a double density Northstar floppy disk controller.

smp

MarsMan2020
August 11th, 2015, 02:43 PM
Is most everyone planning on using this for North Star controllers? How many need it for a Micropolis floppy controller?

The details are long and boring, but the Micropolis controller presents a problem in one particular corner-case related to drive selection that may not be solvable with the board itself.

Mike

I am looking for 1 board for use with a Micropolis controller, and 1 that may be used with either the Micropolis controller or the later Vector controller with the 16 sector Tandon drives.

Chuckster_in_Jax
August 11th, 2015, 08:05 PM
Is most everyone planning on using this for North Star controllers? Mike

Northstar for me.

jgalinat
August 12th, 2015, 03:45 AM
Northstar.

griffk
August 12th, 2015, 05:26 AM
Is most everyone planning on using this for North Star controllers? How many need it for a Micropolis floppy controller?

The details are long and boring, but the Micropolis controller presents a problem in one particular corner-case related to drive selection that may not be solvable with the board itself.

Mike

Northstar - Pls put me down for 2 bds, as already rqstd--thanks!

gwk

litterbox99
August 12th, 2015, 02:57 PM
NorthStar

Nama
August 13th, 2015, 04:27 PM
My two ordered were for N* DD controller boards.

deramp5113
August 13th, 2015, 05:35 PM
I have an answer for the Micropolis controller problem (same applies to the Vector Graphic HD/FD controller for the 16 hard sector Tandon drives). The board will have to used in-line with these controllers (i.e., one cable from FDC to the board, another cable from the board to the drives). Using a single connector in the middle of the drive cable (the "T" option) won't work.

This board should also work with the Altair minidisk system (16 hard sectors), and from what I can tell so far, with the
Heathkit systems (10 hard sectors).

To work reliably with most any controller/drive combination, there will be a 9v battery holder on the back side of the board for power. A single battery should last a year or two. No on/off switch is required, it will power itself on and off based on whether the host computer is powered on.

Mike

MarsMan2020
August 13th, 2015, 08:01 PM
I have an answer for the Micropolis controller problem (same applies to the Vector Graphic HD/FD controller for the 16 hard sector Tandon drives). The board will have to used in-line with these controllers (i.e., one cable from FDC to the board, another cable from the board to the drives). Using a single connector in the middle of the drive cable (the "T" option) won't work.

This board should also work with the Altair minidisk system (16 hard sectors), and from what I can tell so far, with the
Heathkit systems (10 hard sectors).

To work reliably with most any controller/drive combination, there will be a 9v battery holder on the back side of the board for power. A single battery should last a year or two. No on/off switch is required, it will power itself on and off based on whether the host computer is powered on.

Mike

One question Mike - if this board is installed, will the drives still work with a 16-sector floppy? Or is it "all or nothing"?

Edit: Nevermind, I see from the original post that you already answered this and the drives will work transparently with either type of disc.

new_castle_j
August 14th, 2015, 12:42 PM
Is most everyone planning on using this for North Star controllers?

North Star for me

deramp5113
September 2nd, 2015, 06:05 PM
Board is here! Made it through hole to make it easier for people to build their own. Now to port the prototype code from a PIC24FJ256 to the PIC16F1824 on this board.

Mike

26245

litterbox99
September 2nd, 2015, 06:19 PM
Very Cool !

Was wondering the status of your project...

I want one to play with...

smp
September 3rd, 2015, 03:44 AM
Excellent news! I can't wait to give this a try!

smp

new_castle_j
September 3rd, 2015, 06:11 AM
Awesome!

Tor
September 3rd, 2015, 07:50 PM
This is so cool that I almost feel I need it, even though I don't actually own a computer using hard-sectored floppies! :)

jaquinn
September 10th, 2015, 10:46 PM
Definitely interested if you are going ahead with a batch of boards. I am in the process or restoring a Northstar Horizon and this will really help.

smp
September 18th, 2015, 03:56 PM
Board is here! Made it through hole to make it easier for people to build their own. Now to port the prototype code from a PIC24FJ256 to the PIC16F1824 on this board.

Mike

26245

Hi Mike,

Is there any update status that you can share?

Thanks,
smp

deramp5113
September 18th, 2015, 07:01 PM
The move from the prototype environment (PIC24FJ processor - 16 bit, 16 working registers, hardware multiply and divide) to the production board with its PIC16F1824 processor (8 bit, one working register, segmented memory, etc.) has ended up being a total rewrite. Good progress so far, but real life hasn't left me nearly as much time as I'd like to work on this lately.

Mike

smp
September 19th, 2015, 04:37 AM
The move from the prototype environment (PIC24FJ processor - 16 bit, 16 working registers, hardware multiply and divide) to the production board with its PIC16F1824 processor (8 bit, one working register, segmented memory, etc.) has ended up being a total rewrite. Good progress so far, but real life hasn't left me nearly as much time as I'd like to work on this lately.


No problem, Mike. Thanks very much for the update.

smp

deramp5113
September 22nd, 2015, 05:01 PM
Here's a video that shows the virtual sector generator (VSG) automatically adjusting for substantial changes in motor speed with a soft sectored floppy inserted. On the top trace, in the middle of the screen, you can see virtual sector 9, followed by the physical index pulse, followed by virtual sector 0. I induce several speed changes during the video using the motor speed adjustment pot on the drive. In each case, you can see the VSG restore proper timing.

Mike


https://youtu.be/NGbYrbXleuI

deramp5113
September 24th, 2015, 12:47 PM
I'm to the point where I'd like to send out a few of the VSG kits to hobbyists who presently have some time to work with the board and give me feedback on any problems they might encounter. I'd like to find people working with the North Star single density controller, North Star double density controller, Micropolis controller, Altair mini-disk controller, and the Heathkit 10 sector controller. Or, if you have some other application, let me know about it.

The complete kit with all parts comes to right around $40 and shipping by small flat-rate priority mail is $6. If you want it assembled and tested, let's say $60 plus $6 for shipping.

Contact me by PM here or at deramp5113 followed by ASCII 0x40 followed by the yahoo domain name.

Thanks!

Mike