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1.44 mb floppy in dos when bios support is only for 720k Floppy

alexfloca

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Jan 27, 2012
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Transilvania, Romania
Hi all,

Does anybody have a clue how a 1.44 Mb floppy drive can be accessed under dos if the bios supports only 720 k floppy drives, the data rate should not be a problem as for the 5,25" floppy drive it supports 1.2 Mb diskettes. I already tried the drivparm in config.sys but without any luck. Maybe I did something wrong.

regards,
alex
 

krebizfan

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Does the drive work in 720k mode? Does it power? Let's eliminate other potential failure points.

What version of DOS are you using? Also, post computer and BIOS information; it is possible that you could have a BIOS that supports 1.2 MB drives but not any form of 3.5" drive. I don't know of any but I have seen multiple references to BIOS updates sometimes being needed. If you are on a system with DOS 5 or 6 and a BIOS dating after 1985, I expect the problem lies in how drivparm or driver.sys was setup.

Post your drivparm; it should be possible with drivparm to do this with any version of MS-DOS 3.1 or later. However, it seems that 3.30 does not support drivparm which was fixed in a 3.30a update. And the drivparm switches have changed in some versions.
 

alexfloca

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Jan 27, 2012
Messages
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Location
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hi, thank you for the reply. The drive is a 1.44M drive and works great in 720k mode with this computer. The PC is a Siemens PCD-2 with bios support for "double density", "high density" (5,25") and " 3,5" inch" floppy drive.

DOS version 5.0, bios is dated 1982.

I tried to setup drivparm as follows:

drivparm= /D:1 /F:7 /I -not working (the drive B can't read any 1.44 mb floppyes)
drivparm= /D:1 /H:2 /S:18 /T:80 -not working (the drive B can't read any 1.44 mb floppyes)
drivparm= /D:1 /H:2 /S:18 /T:80 /I -not working (the drive B can't read any 1.44 mb floppyes)

with the second drive disabled from the Bios
device=C:\DOS\driver.sys /D:1 /F:7 - not working, it "installs" correctly a drive E (i have 2 partitions C and D on the hard drive) but when trying to acces the drive E it just says I have to insert a disc and press enter, but it won't work.
If I try to acces the drive B: it reads from the 5,25" fdd (A drive)
 

Lutiana

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Hang on. Your BIOS supports High Density floppy drives? Well set the B: as high density and try to read a 1.44mb disk and see what happens.

Double Density = 360k 5.25" and 720k 3.5" drives
High Density = 1.2mb 5.25" and 1.44mb 3.5" drives.
 

krebizfan

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I have read that some AT compatibles did not work with DRIVPARM. If nothing else works, try using DRIVER.SYS in CONFIG.SYS.

But everything I see suggests that what you have done should work so either I am missing something obvious or the problem is specific to Siemens models and you may need to make a follow on post to find someone with Siemens experience.
 

alexfloca

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Jan 27, 2012
Messages
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Transilvania, Romania
hi lutiana,

thanks for the sugestion but it doesn't work, if I set it to high denisity it acts like a 5,25" 1.2 Mb FDD.
krebizfan, thank you, I think this might be my case, i tried configuring it with driver.sys but it doesn't work. I guess it will remain like this, at least I can use it as a 720 k FDD.

Thank you all
 

Lutiana

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hi lutiana,

thanks for the sugestion but it doesn't work, if I set it to high denisity it acts like a 5,25" 1.2 Mb FDD.

How does it act like 1.2mb drive? When you format a disk in it? Does it read 1.44mb disks formatted on another machine?

What is the exact wording in the BIOS for the setting?
 

alexfloca

Experienced Member
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Jan 27, 2012
Messages
87
Location
Transilvania, Romania
i tried everything to get the 1.44 MB FDD act as a 1.44 MB FDD on the Siemens PCD but no luck, I will leave it like this and use 720k formatted floppies with it.
 

MikeS

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Dec 23, 2005
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Toronto ON Canada
i tried everything to get the 1.44 MB FDD act as a 1.44 MB FDD on the Siemens PCD but no luck, I will leave it like this and use 720k formatted floppies with it.
Just curious: Who makes the BIOS ROM(s) and is the setup routine built in or do you need a program on diskette?

I assume that drive A is a 1.2MB HD drive, you're positive that the 3.5" HD drive is working perfectly, and the 3.5" HD diskettes are also perfect?
 
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