Macintosh Quadra 900(1991)

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The Macintosh Quadra 900 was sold from October 1991 to May 1992. It was introduced alongside the Quadra 700 as the first computers in the Quadra family of Macintosh computers using the Motorola 68040 processor. The Quadra 900 was more expandable than the Quadra 700 but cost $7,200 U.S. The Quadra 900 could be upgraded to 256 megabytes of RAM, an astronomical amount for the time, when a typical midrange system would come equipped with 2–4 MB. The standard, as-shipped configuration for the 900 was 4 MB. The high RAM and storage capacity, along with the expandability of five NuBus 90 slots and fast 25 MHz processor, made it a very useful computer for scientific or design work. The mid-tower case design features a single 5.25-inch drive bay initially intended to hold a tape backup drive, but was often repurposed to hold a CD-ROM or SyQuest drive during the machines' operational lifespan. Quadra 900s with full complements of RAM were exceedingly rare with 16–30-pin SIMM RAM slots, due to the high cost (many thousands of dollars) of the SIMMs at the time. A new three-mode key-lock system on the front panel can be set to Off, On, and Secure. When set to Off, the machine can't be powered up. In Secure mode, the floppy drive and ADB port are disabled, offering a degree of local protection. System 7.0.1 was included and supports up to Mac OS 8.1. It is the earliest Macintosh model with the ability to run Mac OS 8.