The Profile Hard Drive
The Profile external 5 MB hard drive was released in September 1981 as an optional peripheral for the Apple III, at a cost of USD 3,500. In 1983, Apple released a Profile interface card for the Apple II computer line, allowing Apple II computers to use the Profile as well (except for the Apple IIc, since it was a portable computer without an expansion slot). The Profile was also compatible with the Apple Lisa, without the need for an additional interface card. This hard drive was not compatible with other computers.
In Figure 13, you can see the interface card for connecting the Profile to the Apple III. They were connected using a 25-pin cable. This interface should have been installed in Apple III’s fourth slot.
Internally, the Profile used a Seagate ST-506 hard disk drive, but an interface designed by Apple. You couldn’t upgrade the internal hard drive directly. (This upgrade was possible, but you needed to upgrade an integrated circuit on the logic board.)
Believe it or not, there are still people developing hardware for old computers. Currently, you can buy an X/Profile, which is a Profile emulator based on the Compact Flash (CF) card. It allows you to use a Compact Flash (CF) card as a hard drive for your Apple III. In other words, create an SSD (Solid State Drive) for your vintage Apple III.