Technical Information 1-21Bit 4 Keyboard/Auxiliary inhibit switchWhen this bit is set, it indicates that the keyboard and auxiliary device are not inhibited.The keyboard controller sets bit to 0 when security mode is active.Bit 5 Auxiliary buffer fullWhen this bit is set, it indicates that data received from the auxiliary device is present inthe output buffer.Bit 6 Time-outWhen this is set, a time-out has occurred during transmission between the keyboardcontroller and the keyboard or auxiliary device.Bit 7 Parity errorWhen this bit is set, the last byte received from the keyboard or auxiliary device has anuncorrectable parity error.System MemoryImage P90E and Image P100E configurations ship with 16 MB of RAM. System memorycan be expanded to a maximum of 256 MB. Total address space is 4 gigabytes (GB)maximum. Memory expansion is performed using single in-line memory modules(SIMMs) installed in SIMM sockets on the memory expansion board.The memory expansion board consists of eight SIMM connectors organized into fourbanks. All system memory supports parity. Memory shipped with the system is comprisedof two 2-MB x 36-bit DRAM SIMM modules (which is 2 x 8MB). The first megabyteincludes the standard 640 KB of base memory. The remaining memory is extendedmemory.The SIMM memory sockets accept 4-, 8-, 16-, or 32-MB SIMM sticks. High-speed RAMis 32 bits wide with four parity bits. SIMMs are 1 M x 36 bit (4 MB), 2 M x 36 bit (8 MB),4 M x 36 bit (16 MB), and 8 M x 36 bit (32 MB). There are no switches or jumpers to setwhen SIMMs are added.The system board's eight SIMM sockets are assigned as banks 0, 1, 2, and 3. Each SIMMkit is inserted into a pair of sockets or bank. Bank 0 contains the two standard SIMMsshipped with the system. Banks 1, 2, and 3 are available for memory expansion. Differentsize SIMMs cannot be intermixed within a bank. See Section 3, Options, for installationinstructions and SIMM memory configurations.
