Floppy drive format issues

[KhanTyranitar]

Wondering if you guys can help me out.

I own several vintage machines and one of them, my Tandy 1000sx has an issue with the 3.5” floppy drive. Basically if I put in a DSDD disk and format it, the format comes out at 360k instead of 720k. If I enter “format a: /f:720” or “format a: /t:90 /n:9” I get a “parameters not supported” error.

Now if I format the disk on another machine using the same terms, it works correctly and the Tandy can read and write said disk. In fact if I take a disk that was formatted at 720k using another machine and just use “format a:” it reformats the disk at 720k.

So firstly, anyone know what is happening, and what to do about it. I have tried more than one drive. Both drives are natively 1.44mb drives which I know the Tandy doesn’t recognize or support. But it should work as a 720 drive.

 

[SomeGuy]

What version of DOS are you using?

The BIOS in most 8088/8086 or "XT" class computers will not automatically recognize 720k disks.

You can add a "driver.sys" line to your config.sys to add support as per:
http://www.minuszerodegrees.net/5150_5160/720k/5150_5160_720k_driversys.htm

Or on later versions of DOS use the DRIVPARM= statement in the config.sys instead.

Alternatively, you may wish to use a formatter other than the DOS formatter. Most will format 720k if you tell them to.

I suspect you are not running the OEM version of MS-DOS designed specifically for your machine. That version probably would have been pre-configured for use with the 720k drive.

 

[KhanTyranitar]

What version of DOS are you using?

The BIOS in most 8088/8086 or "XT" class computers will not automatically recognize 720k disks.

You can add a "driver.sys" line to your config.sys to add support as per:
http://www.minuszerodegrees.net/5150_5160/720k/5150_5160_720k_driversys.htm

Or on later versions of DOS use the DRIVPARM= statement in the config.sys instead.

Alternatively, you may wish to use a formatter other than the DOS formatter. Most will format 720k if you tell them to.

I suspect you are not running the OEM version of MS-DOS designed specifically for your machine. That version probably would have been pre-configured for use with the 720k drive.

Thank you for your prompt reply. On this machine I’m using MSDOS 5.0.

I’ll check out that DRIVPARM statement to see if that helps.

The OEM version of dos for this machine came on 5.25” floppies which I don’t have, the machine did not originally ship with a 3.5” Drive. That said, Tandy did offer a drive back in the day which was just a standard 3.5” 720k drive and it supposedly just worked. To me I keep the 5.25” Drive so that I can read disks if I need to.

Oddly enough the formatter used by the MSDOS installer formats the disks as 720k.

As for running the original DOS, there really is no reason to, as it wouldn’t address the issue and it wouldn’t play nice with the XTIDE. (It would work, but it wouldn’t support the full partition size)

 

[Chuck(G)]

Syntax of DRIVPARM