View Full Version : Hardware review: Epson HX-20

Terry Yager
May 29th, 2004, 09:50 AM
Born in 1981, the Epson HX-20 is widely touted as being the first true "notebook" computer; a computer which packs the full power of a desktop machine into a package the size and weight of a small notebook, and which is powered by batteries (which last up to 50 hours on a single charge). The term notebook computer was first coined in reference to this machine, in a review of it in BYTE magazine.
The HX-20 features a full-size, full-stroke keyboard, a good screen (4 lines x 20 char. with graphics), and built-in hard copy output & mass storage devices (24-col. mini-printer & micro-cassette). It is a complete computer system that can be held in the palm of your hand.
It comes stock with 16Kb of RAM, (expandable to 32Kb with an optional expansion interface, which also provides 4 additional ROM sockets for further software expansion) and 32Kb of ROM, which is home to a full-featured version of Microsoft/Epson BASIC, and a monitor program, for system-level programming, byte-by-byte in hex.
Hardware-wise, the HX-20 is a powerful dual-processor machine, with two Hitachi 6301 cmos processors running at 614KHz. The 6301 is a Motorola 6800-compatable single-chip microcomputer, with processing unit, I/O and memory (4Kb ROM, 128Bytes RAM) all on-chip. The two processors run in a slave/master configuration, and communicate with each other via a high-speed (38,400bps) internal serial connection. They divide the duties of the CPU between themselves, with each being responsible for certain hardware and tasks.
This computer is very desirable as a collectible, in that it was the first of it's kind, and therefore set the standard for all other notebooks to come. The good news is that they are still easily obtainable for relatively little money, with current prices ranging from around $20.00 for a used one at on-line auction sites, up to $799.00 for a brand-new one at this website: http://www.notebooksupplies.com/epson/hx20.html . This situation is subject to change in the very near future, as collectors grab up the remaining available units. If you find the opportunity to get one for a reasonable price, I highly recomend that you do so, before they all disappear into museums and private collections.