The PowerBook 145B has a single motherboard expansion
slot addressed along a 32-bit memory bus. This
computer requires standard 100ns pseudostatic
RAM modules (PSRAM) in either 2MB or 4MB capacities,
as it shipped in a 4MB default configuration with
one vacant expansion slot. While the PB145B accepts
memory that is compatible with the earlier PB140,
PB145, and PB170, it would be helpful nonetheless
to mention the model number in the Comments field
of the order form when purchasing PSRAM upgrade
While the PowerBook 140, 145 and 170 all share
a common motherboard architecture with 2MBs of
soldered PSRAM and a 2MB PSRAM expansion card,
the PB145B includes 4MB of soldered PSRAM,
which enables expansion beyond 4MB without the
necessity of wasting a 2MB PSRAM expansion card.
The Motorola 68030 on the PB145B daughtercard
runs at 25 MHz, but lacks a Motorola 68882 FPU.
One peculiarity of the PB140, 145, 145B and 170-series
is that they do not support SCSI Disk Mode. All
four of these PowerBooks address memory along
a 32-bit data path.
These PowerBooks were the
first mass-distributed 'Books and were likely
to be found in your local Circuit City or other
computer store back in the early 1990's.
Related Links : wikipedia.org - lowendmac.com