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PhilipA
February 28th, 2014, 08:09 AM
I ran into an interesting conundrum yesterday.

I have "upgraded" my Compaq Portable to use a 3.5" drive and a half height 5.25" drive. It uses the original controller card. The 3.5" drive reads 720k disks perfectly, will access the entire thing, read/write fine etc., but DOS 6.22's FORMAT.COM refuses to accept it's anything other than a 360k drive.

Any resolution to this? I mean, I can format floppies in a different machine and use them, but it would be useful to be able to format 720k on the computer itself.

Thanks

--Phil

MikeS
February 28th, 2014, 08:54 AM
I assume you've tried the /F: and /T:/S: options?

Chuck(G)
February 28th, 2014, 09:17 AM
Did you include a "DRIVPARM" statement for the drive in CONFIG.SYS?

PhilipA
February 28th, 2014, 10:50 AM
I assume you've tried the /F: and /T:/S: options?

Yes, yes and yes. Each time I try to do those, it'll give me an invalid parameter complaint.



Did you include a "DRIVPARM" statement for the drive in CONFIG.SYS?

No, I did not. It's been a while since I played with DOS on an every-day level. I'll give that a try. Thanks!

--Phil

modem7
February 28th, 2014, 12:59 PM
The same issue is seen with in the IBM PC (5150) and early models of the IBM XT (5160).
Presumably, it is due to the lack of support in the motherboard BIOS for 720K diskettes.


Did you include a "DRIVPARM" statement for the drive in CONFIG.SYS?

No, I did not. It's been a while since I played with DOS on an every-day level. I'll give that a try. Thanks!
Or DRIVER.SYS
See http://www.minuszerodegrees.net/5150_5160/720k/5150_5160_720k_driversys.htm

vwestlife
February 28th, 2014, 02:28 PM
Or DRIVER.SYS
See http://www.minuszerodegrees.net/5150_5160/720k/5150_5160_720k_driversys.htm

DRIVER.SYS takes up RAM. DRIVPARM does not.

Or, the easiest option is to use SETBPB35:

ftp://ftp.oldskool.org/pub/tvdog/tandy1000/misc/setbpb.zip

This program will set the device characteristics for the A or the B diskette drive to indicate that the drive is a 720K drive instead of a 360K drive. It requires DOS 3.2 or later.

The only command line parameter is the drive letter (A or B).

For example, to indicate that your B drive is a 720K 3.5" diskette drive:

SETBPB35 B