What Is REX
REX is completely plug and play flash memory upgrade. REX plugs into the Option ROM slot, with no soldering or necessity to open the laptop case.
REX provides support for up to 16 in-circuit selectable option roms. That means, you can have 16 different software packages on one Option ROM, and select between them without physically unplugging anything.
In addition, REX is in-circuit, software reprogrammable. That means you can change, patch, or replace an Option ROM image without any special hardware or physically unplugging REX.
An additional feature is a facility for freezing/thawing up to 16 RAM images to/from flash. This offers an easy way to quickly backup all RAM to flash, or switch between multiple snapshots of RAM. This is similar to the "fast switch environments" on Remem: it would be like having multiple laptops in the same case!
For advanced users, REX distinguishes between traditional option rom software, and alternative OS software which runs from the option rom memory location. This allows for some interesting future capabilities like CP/M or a FORTH based system.
REX comes pre-programmed with REX Manager software. REX Manager allows you to pick which of the 8 ROM images is the one currently in use.
REX Manager operates "behind the scenes" to make sure the currently selected Option ROM image is automatically enabled on every power cycle. This is an impressive trick since REX does not receive power while the laptop is off (unlike the RAM memory circuit).
Also, REX Manager is able to do this while using a minimal amount of RAM space (about 10 bytes)!
Advanced BASIC ROM Replacement Mode (OPTIONAL)
For users with the do-it-yourself spirit, an optional feature of REX can be enabled.
With a single wire soldered in place, REX permits BASIC ROM replacement!
This means that you can disable the built-in BASIC/TEXT/TELCOM ROM on your motherboard and replace it with a specific block of REX flash memory. Typically, this will be the same BASIC/TEXT/TELCOM ROM image we know and love, with a few changes. So, you can upgrade your Model T with little tweaks like Y2K, the lomem patch, new character sets, put your name on the main menu, etc.
Installing REX Manager - It's Easy
From a cold restart, power cycle the laptop and the simply type
will install the REX system.
You should see a program in the Menu called REXMGR.BA. Running this program will always start the REX Manager software.
REXUPG.CO is a utility that allows the user to upgrade the internal REX Manager software.