With the Motorola 68030 processor starting to show its age, Apple had been working on machines built around Motorola's latest processor, the 68040. In October 1991 they became available and the world was introduced to the Quadra range (and later the Centris range which used the 68LC040 - a 68040 but minus a floating point unit), initially in the form of the Quadra 700 and the Quadra 900.

The Quadra 900 shared the same form factor as the 700 in that they were both tower machines but while the 700 would sit happily on your desk, the 900 was a monster of a machine that simply had to be placed on the floor. It may only have offered one front accessible drive bay but internally the 900 could support a stack of drives and this made it ideal as a server, a fact not hindered by the addition of two separate SCSI busses (although under System 7.0-7.1, these were 'folded' together so that only 7 SCSI IDs were possible - the 8th being reserved for the system as per usual).

Note: When using System 7.0-7.1, the two SCSI busses must be treated as one with respect to SCSI IDs - this includes internal AND external devices.

The 'bigger is better' philosophy carried through to the motherboard and Apple allowed up to 5 NuBus cards to be plugged in (3 'standard' 15 watt slots and 2 'high power' 25 watt slots) and a huge 16 30-pin SIMM slots which allowed up to 256Mb of RAM to be installed.

Running at a reasonable 25MHz (although with the 68040 this was enough to allow it to run OS 8) the 900 was a great machine that allowed excellent opportunities for expansion and even sported a built in Ethernet port which used the same new AAUI connection as seen in the Quadra 700 (the Quadra 700 and 900 were in fact the first machines with Ethernet built in). Also like the Quadra 700, the 900 couldn't support 16-bit colour at any resolution, despite the fact that it could supply 24-bit colour (depending on the amount of VRAM installed). Unlike the 700 (and indeed any other Mac before it) the 900 was the first Mac to sport a locking key, allowing users to lock the machine to 'off', 'secure' or 'on' - proof, if proof were needed, that Apple definitely aimed this at the server market.