Page "Tandy 1000" Paragraph 6

For most Tandy 1000 models other than the compact EX and HX that did not come already equipped with a hard drive, Tandy offered hard disk options in the form of " hardcards " that were installed in one of the computer's expansion slots and consisted of a controller and drive ( typically a 3. 5 " MFM or RLL unit with a Western Digital controller ) mounted together on a metal bracket.

Although this arrangement provided a neat physical coupling between the controller and the disk, single-sector internal transfers and dependence on the speed of the host machine to transfer data to memory meant that a trial-and-error approach was still needed to set the disk interleave correctly to ensure optimum transfer rates.

Even then, transfer rates could be as low as 40kB / s for 8088 and 8086 machines.