The T-Disk comes in two sections. The first section is the side-car which connects to the side expansion slot of the A1000. This contains the controller (probably SCSI), 1MB of RAM and mouse port as extensions as it covers those on the A1000. This unit is probably electrically compatible with the A500, but the dimensions may prevent it from being used correctly. The second part is the hard disk, was was a 20MB unit in an external case. This also contained an on/off switch. The T-Disk also contained an additional serial port, however it is non-functional as the design was never completed. The T-Disk does not support autobooting as drivers must be loaded from disk first. The connections between the T-Disk and the A1000 can be quite loose, unless held together tightly.
Thanks to Jeff Heliige