Tandy 1000sx and Flippy Disks.

[dabone]

Just wasted a hour of my life trying to figure out why my 1000sx was formatting floppies 170k.
The disks I was using were originally commodore disks with the extra write protect hole cut in the other side.
The drives in my 1000sx detect the other hole and apparently force the drive into single sided mode.
A little bit of tape on the floppy and it's working much better now.

Later,
dabone

 

[deathshadow]

A number of tandy 360k floppy drives recognized flippies 'out of the box'. There used to be a way to tell the 1000SX to 'flip' which side it's reading without taking the disk out, but for the life of me I can't remember how.

Though I do remember on my model 3 where I replaced the internal drives with 80 track DSDD, I actually had it set up so that each 'side' was treated as a separate drive number since TRS-DOS didn't know what to do with double sided drives.

 

[vwestlife]

I thought Tandy just used "off-the-shelf" TEAC drives in the 1000 and 1000SX... does it really have another write protect sensor on the other side?

 

[deathshadow]

I thought Tandy just used "off-the-shelf" TEAC drives in the 1000 and 1000SX... does it really have another write protect sensor on the other side?

Oddly usually it's not the write protect that's present, it's a second cylinder detection optic. Literally it sees the second hole so it knows it's a flippy after one revolution.

 

[vwestlife]

Oddly usually it's not the write protect that's present, it's a second cylinder detection optic. Literally it sees the second hole so it knows it's a flippy after one revolution.

Ah, so that's for "proper" flippy disks which have the round sector hole on both sides, as opposed to homemade flippy disks where you just take a hole puncher to cut out the write protect notch on the other side, because most computers with single-sided drives don't need or use the sector hole.

 

[Chuck(G)]

I don't understand any of this. :huh:

If you're working with a commodity drive, there's only a single index sensor. In other words, the drive is blind to the "other" index hole on a flippy, so it has no way of telling.

So--please elucidate.

 

[dabone]

I just opened my other 1000sx I have at work, and both the 5.25 drives on it have nothing to detect the other write protect hole (or index hole).
I'll get around to looking at the drive on the one I have at home and see if it's different. I can't think of any other reason that putting a sticker on that hole would make
any difference if there isn't a sensor.

Later,
dabone

 

[Great Hierophant]

Do flippy disks exist in the IBM PC world? Are they supported in the single-sided drives of the original IBM PC? Any software known to use them for the PC platform? A bog-standard drive like the TEAC FD-54/55, used in the Tandy 1000 series, is double sided and would have no particular need to read a true flippy disk.

 

[Chuck(G)]

There were flippy disks in the 8" world. While there may have been some use for them early on in the IBM PC world, I've never run into any, as the move to double-sided drives occurred very early on.

 

[vwestlife]

While there may have been some use for them early on in the IBM PC world, I've never run into any, as the move to double-sided drives occurred very early on.

Single-sided drives remained available as a (cheaper) option on the IBM 5150 PC for quite a while after double-sided drives were introduced, but just like the mythical base model 16K cassette-only 5150 (or the driveless PCjr, for that matter), I'm sure nobody in their right mind actually ordered one that way; it was all about being able to advertise a lower price.

 

[dabone]

Ok, I got home and yanked apart the 1000sx and the floppy in it has NO sensors over there either. Weird, also, the disks I could only get to format as 170k, now format fine at 360, the drive was very dusty and I cleaned it some, but wtf. I tried 3 different floppies and they all did it, now they all work fine.

Lack of sleep, gremlins, etc, I have no idea.

Later,
dabone