• Please review our updated Terms and Rules here

What uses hard sectored disks?

Torch

Torch

Experienced Member
Joined
Sep 7, 2018
Messages
172
Location
Indiana
I was testing out a 5¼ drive I got off eBay and thought there was something wrong with it as I kept getting a bad sector error when trying to format disks.
I was using a fresh box of BASF FlexyDisks, DSDD (certified for 96tpi) and just happened to notice there were 2 timing holes placed closely together? As I rotated the disk there are a total of 17 holes unevenly spaced.
I've heard of hard sector floppies but thought they were pretty much obsolete after 8". These are the first I've come across and I have like 5 boxes.
Needless to say, they won't work in my PC, the Tandy 1000EX or my Model III. Curious as to what systems were using these back in the day? Portable word processors maybe?

For fun, I cut up some write protect stickers into small strips and placed them over 16 of the holes using tweezers. The disk now identifies as a soft sector and works fine. :)
 
A number of systems used hard sectors like Northstar and Heathkit. IIRC, the hard sectored disks were required with certain controllers and drives so it was possible to have two virtually identical systems with one needing hard sectors and the other not.
 
Theses disks are quite rare and it's not possible to use them with a PC and many other systems which requires only one index hole for the beginning of a track (sector 0).

But those peoples having such systems today which suppported only hard sectored disks really would be happy to have them. This might be some cp/m machines or even more exotic. Would you give them away and maybe ship worldwide? If so I would ask if there is some demand in a german forum, I remember someone over there was searching for such disks a while ago without success.
 
Yes, it was strange looking at a Commodore disk drive that used a stripped-down Shugart SA400 with no index hole detector (or track zero microswitch). Everything down to a price point...

Dave
 
With the correct drive, you could even do this with 8" floppies. Some 8" drives separated sector holes from index ones and brought those to separate outputs. That could be confusing if you received a batch of HS 8" floppies with no indication of what the source system was. You get all set up to digest hard-sectored stuff, only to discover that the sector ID headers don't match up with the index holes--HS disks were used because they were available.
Except for some very early 8" stuff (such as the Memorex 650 floppies, which used 8 sector holes punched on the outside edge of the cookie), all 8" HS disks were 32 sector. This differs from the 5.25" media which could be 10 or 16 sector.
 
Polymorphic System88 used hard sectored 5-1/4. Hard sectored disc are simpler to make controllers for. It wasn't until soft sectored controller chips were popular that soft sectored became more standard. Later Polymorphic systems used a soft sectored board with a Z80 to control it. This was while the main processor was still a 8080. It used a memory mapped read/write buffer, for sector data. I thought it was funny that the CPU on the controller board was more powerful than the main CPU.
Dwight
 
It's noteworthy that IMSAI used a 2-board set for their soft-sectored 8" drives; one of the boards used an 8080, just like the main CPU board, I thought it remarkable that the IMSAI S100 system got along with that setup, while the Intel MDS800 used a 2 board setup that used 3000 series bit-slice control logic (IIRC it ran very hot) to do the same thing.

There were a couple of very low-end systems that used a USART for their floppy control.

It's not at all unusual for peripherals to have CPUs that run faster than the main CPU. Graphics cards are a good example of this, but I remember that one of the standard packages for the Morrow MD3 system involved a Mannesmann-Tally dot matrix printer that had an 8088 inside.
 
kgober said:
Some systems ignore the sector timing holes altogether and won't care whether you use hard sectored or soft sectored floppy disks. Commodore 8-bit systems, for example.
Click to expand...

Does the 1541 ignore them or would you talking about drives for the PET?
 
I believe the original Heathkit H8 & H17 HDOS setup used only DS/DD/RH10 media with 10 hard sectors. The later H89 systems had the option of having a hard sector controller and using media compatible with the H8/H17 or a soft sector controller that was compatible with Heath's version of CP/M.
 
Torch said:
Does the 1541 ignore them or would you talking about drives for the PET?
Click to expand...

So far as I’m aware all Commodore drives using GCR don’t care about the index holes. Neither do Apple II floppy drives. This is why it was easy to turn normal floppy disks into “flippy“ disks for these systems by just cutting new write protect notches.
 
Eudimorphodon said:
So far as I’m aware all Commodore drives using GCR don’t care about the index holes. Neither do Apple II floppy drives. This is why it was easy to turn normal floppy disks into “flippy“ disks for these systems by just cutting new write protect notches.
Click to expand...

I have also seen Commodore diskettes that had multiple index holes like this one (obviously you can't see all of the holes). Maybe it was only Commodore Canada but they used whatever they could get their hands on. This is an original Commodore diskette with 17 holes.

Commodore_BBS.JPG
 
You must log in or register to reply here.
Back
Top