IBM ThinkPad T20 series

The IBM ThinkPad T20 series was a series of notebook computers introduced in May 2000 by IBM as the successor of the 600 series and the first model of the T-series which exists today under Lenovo ownership. Four models were produced, the T20, T21, T22, and T23; the series was succeeded in May 2002 by the ThinkPad T30, but was produced until July 2003.
Features.
The T20 series succeeded the 600 series, adding new features such as S-Video output, an Ethernet port, and the UltraBay 2000 hot-swappable bay. The graphics card was upgraded from the 4MB NeoMagic 256ZX which was used in the 600X, to an 8MB S3 Savage (16MB on T23 models) which was capable of rendering 3D graphics in hardware. The ThinkPad T23 was also the first ThinkPad laptop model to offer an optional WiFi connection via a Mini-PCI card, using wireless antennas which were built into the lid on select upper-end models.
The T20 series originally shipped with either Windows 98, Windows 2000, or Linux, with later T23 models shipping with Windows XP. All T20 models were capable of running Windows 3.x, Windows 95, Windows NT 4.0, OS/2 Warp 4, or Windows Me as well as various Linux distributions. Additionally, the T23 was capable of running Windows Vista or Windows 7, if equipped with at least 512MB of memory.
One common problem of the earlier T20 series was a hardware defect which caused the machine to suddenly stop working and begin blinking the hard drive and power indicators. The machine would not power on. This became known as the "Blink of Death". In addition, on some T23 models, the rear memory slot could fail, rendering the machine only able to use up to 512MB of memory, rather than 1GB. Another common issue with the T23 was that one of the coils, near the CPU, could break off the motherboard due to cold solder joints. This caused all sorts of issues like being unable to boot or hard lockup/freeze.