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 
                            modules.  
                              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   |