The HD8+ is a SCSI controller which connects to the side expansion slot of the A500/+. The HD8+ has 4 x 30-pin SIMM sockets that can utilize 1Mx8 or 4Mx8 SIMM modules. Versions of this unit may exist which use the special 32pin GVP SIMM32 SIMMs instead of the standard 30pin SIMMS, but this has not been confirmed.

This is a GVP (Great Valley Products) drive

    * Combination eight (8) megabyte, zero-waitstate, FastRAM controller and ANSI XT3T9.2 compatible SCSI interface.
    * High performance DMA transfers to and from hard-disk.
    * SCSI data transfer rates of up to 3.58MB/sec.
    * Auto-configs both Fast RAM and SCSI interface.
    * Internal 50-pin SCSI connector.
    * External 25-pin SCSI connector (DB25).

Our unit and the power supply unit is complete with the original box and was kindly donated by Shane MxcDonnell

A GVP A500 HD+ with a 'very rare' 32 pin memory fitted (rather than the more common 30 pin, as generally described on your website) exists. This is fitted with 4x1mb simms (populating all 4 simm sockets) and the scis hd is the original 121mb. I have yet to come across and 32 pins simms larger than the 1mb type, already fitted.
Note kindly added by Keith Emer