Self booting 3.5 floppy

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Iudex
Posts: 16
Joined: Fri Oct 26, 2012 6:11 am

Self booting 3.5 floppy

Post by Iudex »

To make transfering files easier from a modern computer to the pcjr I put a 3.5 720kb floppy in the pcjr. I have a dos2.1 image file on the 720kb disk but the pcjr says it is not a bootable disk. It is formatted as FAT 12bit. Does any one have any suggestion of how to proceed?

Thank you
jmetal88
Posts: 811
Joined: Sun Jul 25, 2010 10:22 am

Re: Self booting 3.5 floppy

Post by jmetal88 »

The PCjr can only read 360k disks at boot. You can use a 3.5" floppy drive, but you have to format the boot disk as if it were a 360k disk. You can put a DRIVPARM line in your config.sys file to tell DOS it's really a 720k drive.
Iudex
Posts: 16
Joined: Fri Oct 26, 2012 6:11 am

Re: Self booting 3.5 floppy

Post by Iudex »

I was able to format the 720k disk to 360k. The pcjr did not give me any messages with format but it did not load the files either; it just gave me a blinking cursor. Am I missing something? Thank you.
Brutman
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Re: Self booting 3.5 floppy

Post by Brutman »

Are you sure it is a real 720KB floppy, or is it a 1.44MB floppy?

I've had that problem with 1.44MB floppies. They will pass the diagnostics, but not boot. But on the real 720KB drives that I have tried it works fine.

You might be better off finding an old BackPack 3.5" floppy drive that connects to the parallel port. They work fine on the PCjr for data transfer.

Mike
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