Technical Information 1-5
Processor
The PowerMate P series of computers use the following Pentium processors:
n
PowerMate P150 — 150-MHz processor with an internal speed of 150 MHz and
an external speed of 60 MHz.
n
PowerMate P166 — 166-MHz processor with an internal speed of 160 MHz and
an external speed of 66 MHz
Each processor has 16 KB of write-back primary cache and a math coprocessor. The 16 KB
primary cache provides 8 KB for instructions and 8 KB for data.
The processor is an advanced pipelined 32-bit addressing, 64-bit data processor designed to
optimize multitasking operating systems. The 64-bit registers and data paths support 64-bit
addresses and data types.
To use the Pentium processor’s power, the system features an optimized 64-bit memory
interface and complementary synchronous pipelined 256-KB secondary cache.
The processor is compatible with 8-, 16-, and 32-bit software written for the Intel386™,
Intel486™, and Pentium processors.
To accommodate future technologies and work requirements, the Pentium processor comes
in a 320-pin zero insertion force (ZIF) socket. The socket provides an upgrade path to the
next generation processor.
Secondary Cache
The system board contains 256 KB of secondary cache, external to the processor. The
cache uses 15-ns SRAM that allows data to be sent or received from the cache with one
wait state burst. Cache memory improves read performance by holding copies of code and
data that are frequently requested from the system memory by the processor. Cache
memory is not considered part of the expansion memory.
The cache is connected directly to the processor address bus and uses physical addresses. A
bus feature known as burst enables fast cache fills. Memory areas (pages) can be designated
as cacheable or non-cacheable by software. The cache can also be enabled and disabled by
software.
The write strategy of the cache (primary and secondary) is write-back. If the write is a
cache hit, an external bus cycle is not generated and information is written to the cache. The
system caches the following regions:
n
all system memory, including 0 to 640 KB and all memory present above 1 MB
(see the following subsection for a system memory map).
n
system and integrated video controller in BIOS
