TI-99/4A FAQ: Disk Drives

Common Drive issues

Floppy disks and drives are all very old at this point and are experiencing failures related to old capacitors,  broken/burned out optical sensors and LEDs etc.

Troubleshooting steps:

  • clean the drive heads, rails and lubricate with white lithium grease
  • inspect drive for broken parts or burned out LEDS
  • replace the cable with a new one, NO TWISTS

Drive options

TI made a stand alone disk controller and a PEB card that supported up to DS/SD diskettes. There is an 80 track modification available from hummingbird eproms to add 80 track drives to this controller.

Corcomp made a PEB disk controller and a sidecar “9900 Micro” that supported up to DS/DD diskettes.  http://mainbyte.com/ti99/hardware/9900_micro/9900_micro.html

Myarc made a PEB disk controller that supported up to DS/DD diskettes.

Myarc also made a HFDC (hard, floppy disk controller) for the PEB that will support up to 80 track DS/DD disks on a 4/a and fully format 1.44mb HD disks on a Geneve (with the appropriate drive).

Drive Emulation

You can hook up a GOTEK drive emulator with 3rd party firmware (I recommend flashfloppy.com) and use it as a SS/SD-DS/DD 5.25″ drive 40 or 80 track, DS/DD and DS/DD 3.5″ drive 40 or 80 track. Obviously you need a disk controller that supports the format you are trying to use.  Flashfloppy will use v9t9 format disk images as well as HXC format.

The Lotherek HXC also works well, however it is more expensive and less feature rich than the GOTEK.  To use this you must convert all your disk images to their HXC format. https://lotharek.pl/

TIPI provides drive emulation for level 1 and level 2 access through the map function. Allowing you to point DSK1. DSK2. DSK3. and/or DSK4. to whatever folder you want on the TIPI. drive. DSK0. always points to the root of the drive.


Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.