The L40SX is a well-built IBM laptop that was part of the PS/2 (Personal System/2) lineup, released around 1991. It has a 20MHz 386SX processor, with a hardware switch to adjust the speed between Automatic and User-Defined.

It has a monochrome sidelit screen (since this was before the CL57SX), but it’s surprisingly crisp and clear. The keyboard is the best laptop keyboard I have ever felt; they tried to imitate the IBM Model M Keyboards of the time! In fact, IBM sold a version of this laptop’s keyboard with a built-in TrackPoint, the IBM Model M4-1.

My first L40SX came with 4 MB of RAM; my second came with 6 MB. Over the years, I’ve replaced the CMOS battery, hard drive (standard IDE with a Dynamic Drive Overlay seems to work fine) and batteries. These are neat machines, but be aware that if the CMOS configuration is lost, you will need to boot from a floppy to reconfigure the machine (as was common on PS/2 machines of the time). Without this, the laptop will not be able to see the hard drive configuration, and will boot to a built-in ROM version of the BASIC programming language.

Revised on December 21, 2019