Question about the PEB and disk controller

[Tuxon86]

Hi!

 

I may be able to get my hand on a PEB soon and I’m wondering which half height 5.25” floppy drives are compatible with the stock Ti controller?

I’d like a dual drive setup with either two actual floppy drive or one floppy and a gotek (if that’s possible).

[+arcadeshopper]

 

[+Ksarul]

The only half-height floppies you really have to worry about in the PEB are the ones from Qume (Qumetrak-141 and 142). They are fine as a single PEB drive, but they draw too much power when trying to use two of them. They are also belt-driven drives, which can be problematical 30 years on. . .

 

EPSON drives are sort of edge cases--sometimes they work fine, sometimes they draw too much power. It basically depends on the drive lot.

 

The real key is to make sure the drive you are trying to use is 360K and 300 RPM. 720K drives will also work (with some controllers), but should be avoided unless you know that you have a controller that can handle them. Avoid 1.2M drives like the plague. They WILL NOT WORK. Stay away from the combi-drives too, as the 5.25 drives in those are 1.2M.

[+OLD CS1]

1 hour ago, Ksarul said:

Stay away from the combi-drives too, as the 5.25 drives in those are 1.2M.

And no matter how hard you try, following standard "setting this will set the drive in 360k mode at 300rpm," you will be defeated.

[apersson850]

I once (1983 or so) installed two Teac FD 55B. They still work and consume little enough to be driven by the PEB.

[+OLD CS1]

1 hour ago, apersson850 said:

Teac FD 55B

These are my favorites.  Rock solid.

[+Ksarul]

7 hours ago, apersson850 said:

I once (1983 or so) installed two Teac FD 55B. They still work and consume little enough to be driven by the PEB.

I think that easily 2/3 of all PEB dual disk upgrades used the FD 55B drives. User's Groups were facilitating mass buys of them to get better pricing too. I had six or eight of them at one point. I later added some FD 55Fs to some of my systems for 80-track capability (I have a couple of Myarc controllers, which made that an option, as none of the other controllers would be able to use them).

[apersson850]

That could be. Lack of internet back then lead to personal research. I found them advertised or something, and thought they could work as dual drives in the PEB.

Later I changed to CorComp controller, got 360 K on each drive instead of 180, and eventually added another box with two more drives. The last two are IBM drives (made by Shugart) that came from early IBM machines, where they had two standard height drives (A: and B:) in their box. Some replaced them with two half-height drives (Teac FD 55B, maybe?) in one hole in the box and put a 5 or 10 megabyte hard drive in the other hole. Then you got these IBM drives as leftovers. I got them for free. Good when I was a student.

[Geoff Oltmans]

On 10/25/2022 at 12:18 AM, OLD CS1 said:

And no matter how hard you try, following standard "setting this will set the drive in 360k mode at 300rpm," you will be defeated.

The biggest problem with high density drives is that the heads are smaller and thus write smaller tracks than are meant for 40 track drives, so interoperability with 40 track drives is problematic. Reading disks is okay, but writing data back is an issue.

[+OLD CS1]

16 minutes ago, Geoff Oltmans said:

The biggest problem with high density drives is that the heads are smaller and thus write smaller tracks than are meant for 40 track drives, so interoperability with 40 track drives is problematic. Reading disks is okay, but writing data back is an issue.

That may be the biggest problem on a PC, but only one of a couple of problems on the TI.  I know about the half-track issue.  On most drives with which I worked, setting low-density mode will double-step the head.  In my experience with hours spent on it, the problem was the drives would not reduce speed from 360rpm to 300rpm when in low-density mode.  From what I understand, only the Myarc controller and a Geneve is capable of utilizing HD floppies.

[Tuxon86]

Well, I won an auction for a “new” PEB on eBay. https://www.ebay.ca/itm/285003279126
Now I need to get a disk controller, a 32k ram module and a RS232 card. I’d like to find at least one floppy drive also, or if the controller permit it, two half height.

 

I’m going to make a post in the Wanted sub forum for those. I’ve a few machine and devices that I’m willing to sell or trade for.

[Geoff Oltmans]

13 hours ago, OLD CS1 said:

That may be the biggest problem on a PC, but only one of a couple of problems on the TI.  I know about the half-track issue.  On most drives with which I worked, setting low-density mode will double-step the head.  In my experience with hours spent on it, the problem was the drives would not reduce speed from 360rpm to 300rpm when in low-density mode.  From what I understand, only the Myarc controller and a Geneve is capable of utilizing HD floppies.

Never really considered that but that makes sense. I guess if the controller can't compensate by using an appropriately higher recording speed then you'd have issues there too.

 

[Geoff Oltmans]

Apparently, the TI disk controller uses the index hole because my attempts to make flippy disks for my single sided drive fail miserably. Heh

[HOME AUTOMATION]

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[apersson850]

Soft sectored disks in the TI 99/4A use the index hole for the "write track" command to the disk controller chip. That command is used to format the disk. Once that's done, you can plug the hole. It will work anyway for sector access.

[+arcadeshopper]

20 hours ago, Geoff Oltmans said:

Apparently, the TI disk controller uses the index hole because my attempts to make flippy disks for my single sided drive fail miserably. Heh

I sell disks already punched

[Tuxon86]

16 minutes ago, arcadeshopper said:

I sell disks already punched

How violent you are… 

[+OLD CS1]

1 hour ago, arcadeshopper said:

I sell disks already punched

Generally, I just swear at mine.

[Tuxon86]

Today, all you can do is put them in time out, but not in a stern way so as to not hurt their feelings…

 

You’ve been a bad, bad floppy today. But mommy still love you! I just want you to reflect on what you did…. Oh hell, Arcadeshopper was right, let me punch her a couple of time… It’s for her own good…

 

oh, maybe I just did a faux pas… I should’ve asked what was that floppy preferred pronoun and not just use “her”… what to do now!

[GDMike]

At least not to burn em at the stake..

damn witch floppies can be problematic.

[RXB]

I got away from 5 1/4 floppies as fast as I could for good reasons:

1. SLOWER!

2. DINKY STORAGE!

3. 5 1/4 drive is twice the size of a 3 1/2 drive.

4. 3 1/2 drives are double sided and double density.

5. Two 3 1/2 drives draw less power and less stress on Power supply.

6. I can put a 3 1/2 disk in my pocket, try that with a 5 1/4 disk.

7. 3 1/2 drive has a cover built into it and a 5 1/4 has to have a separate jacket to keep track of and use.

8. Started using USB as soon as they came out for obvious reasons.

9. Now with TIPI use WIFI to my PC so even better and less noise plus unlimited size.

[Tuxon86]

18 minutes ago, RXB said:

I got away from 5 1/4 floppies as fast as I could for good reasons:

1. SLOWER!

2. DINKY STORAGE!

3. 5 1/4 drive is twice the size of a 3 1/2 drive.

4. 3 1/2 drives are double sided and double density.

5. Two 3 1/2 drives draw less power and less stress on Power supply.

6. I can put a 3 1/2 disk in my pocket, try that with a 5 1/4 disk.

7. 3 1/2 drive has a cover built into it and a 5 1/4 has to have a separate jacket to keep track of and use.

8. Started using USB as soon as they came out for obvious reasons.

9. Now with TIPI use WIFI to my PC so even better and less noise plus unlimited size.

Oh I get all of these point. When I say I want a two drive system, I'm not set in stone that they must be 5 ¼ floppy drive. After all, the biggest use case for them will be for my own code. I may even go with a Peb version of the Tipi for the networking convenience. But I really wanted a real Peb since I was a teenager and RPi are pretty much made from unobtanium presently. A Gotek and either a 5¼ or a 3½ would be ideal. I think Arcadeshopper sells some modded controller for 80,80,40 and other configs.