This is written for and to anyone who happens to have an Epson Px-8 (Geneva) portable computer and who has not yet been able to make it useful. Part of your problem may be that you are trying to use software that comes with the machine, e.g. "portable Wordstar" or that you are trying to read software in from tape each time prior to execution. In either case, one would recommend that you burn useful software, available for free on this and other bulletin boards, onto rom chips. The rom chip type to use is the 27c256, made by several manufacturers. Eli Heffron / Solid State Sales -- Hampshire Street in Cambridge. Or order from the West Coast discounters, JDR Microdevices, etc. Try to get 200 nanosecond chips if you can. I do not know how fast the chips in fact have to be to work satisfactorily with the machine. I do know that 200 ns works great. 300 probably works as well. Beyond that I don't know. The "c" (for Cmos) is very important. These draw less power than the normal Eprom. You will get just under 32k of files on a 27c256 chip, the precise amount depends upon the number of files and how you can fit them together. (The rom slot in the expansion "wedge" will take a 27512 as well as a 27256. I believe, as well, that two 27c256 chips can be combined in the two carriers for a not quite 64k disk.) You may have to erase the chips. Done using ultraviolet light. Borrow an eraser. Or build one: You will need a small germicidal UV bulb (G8T5 is plenty big), which you can get from one of the big electric supply houses, (Standard, Mass Gas & Electric, etc.) for about $20, and a fixture with a starter and ballast, $11 at Grainger's now in Brighton, or $20 as an "under counter fixture" at one of the electrical supply. Wire and a darkroom timer and you are there. Ten minutes will do most roms. Fifteen is sure. Do not look at the light! Best: put the light in a box that closes. You will need to borrow or build a rom burner, or get a nice person to do it for you. (If you ship me the software and rom chip I will be glad to.) Build: $95 from B&C Microsystems in the back of BYTE mag. The only "trick" to the job is in structuring the directory so that the PX-8 operating system understands it. FIRST IMPORTANT PRINCIPLE: The high order address line is inverted to the rom chip. Thus location 4000 hex is location 0000 hex, and vice versa. The directory, which begins at the beginning of the chip, is thus at what any normal person would call location 4000 hex. SECOND IMPORTANT PRINCIPLE: The 'files' begin immediately after the directory. If the last byte of the directory is at 404F hex, then the first byte of the first file is at 4050 hex. If you have those two - everything else follows. Some PX-8 rom directories from Epson produced roms are listed below: 3FF0 FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF ................ 4000 E537 200F FF48 3830 4241 5349 4320 2020 .7 ..H80BASIC 4010 2020 2020 2020 0456 3130 3039 3136 3833 .V10091683 4020 0042 4153 4943 2020 2043 4F4D 0000 0080 .BASIC COM.... 4030 0102 0304 0506 0708 090A 0B0C 0D0E 0F10 ................ 4040 0042 4153 4943 2020 2043 4F4D 0100 0078 .BASIC COM...x Checksum for the rom is: A7CC 4000 E537 203C 6948 3830 4D32 3530 3436 4341 .7