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.
The primary features of REX are:
- REX allows for quick and easy switching between OPTION ROM images. Once the binary software images are loaded into REX, the user can easily jump back and forth between different applications. 16 OPTION ROMs may be loaded, stored and used.
- REX provides the ability to backup and swap working RAM images. At the press of a key, your current RAM contents are saved in REX. Furthermore, you can reload any saved RAM image for use. This creates a library of RAM images, which has a number of uses. 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 is like having multiple laptops in the same case! 16 RAM images may be stored.
- REX includes an interface to TPDD devices (like TPDD, NADSbox, LaddieCon etc) for loading and saving binary images to external storage.
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.
For advanced users, REX provides some additional features:
- 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 also supports "Main ROM Replacement". This means that, with the addition of a single wire, the main rom on the laptop may be replaced by a version stored in REX. This allows for flash-upgradeable main ROM images, to support patches, custom Menu and character sets, LOMEM patch, Y2K patch etc.
REX is available exclusively through Club100.
REX comes pre-programmed with REX Manager software. REX Manager allows you to pick which of the ROM or OS images is the one currently in use, and also supports management of RAM images.
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).
REX Manager is started by running the program REXMGR.BA from Menu.
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.
REXMR.CO is a utility that allows the user to program upgraded main rom images into REX for use in "ROM Replacement" installations.
REX2 will be available in the near future. It provides additional blocks of SRAM, allowing an all RAM mode of operation, for CP/M support.
Rel. 4.3 Beta testing: bug reports/fixes
I should not have sent out the "4.3 beta" a few weeks ago as it was too alpha.
I found a number of bugs that were subtle and affected stability. Now that those are resolved, and the TPDD routines are robust to TPDD problems, I now have a candidate final load. All the features I have considered have been implemented.
R4.3b supports M100/T102 only right now. I will have a T200 R4.3b shortly.
Tested drive targets include: NADSbox, LaddieCon, TPDD-1, TPDD-2
1) fixed in 4.3 - timeout of TPDD 1/2 - after loading an image, a command response times out at the end...need to extend the timeout delay.
Rel. 4.2 Beta testing: bug reports/fixes
1) DONE R4.3 - found error in code - Year bug - the year data is not correctly preserved by REX when RAM images are saved and loaded. Solution - implement a mechanism that maintains the year data properly.
2) directory bug with entry for block 31 - it appears that the name entry for block 31 is not displayed correctly, investigation continuing.
3) DONE R4.3 - sound is disabled - sounds - currently REX uses audible clicks to indicate progress, which can be annoying. Solution - disable audio, replace with some other mechanism.
4) DONE R4.3 - directories are now sorted in descending order of date/time - directory order - current directory entries are displayed in order of block number, which is problematic since this causes reordering whenever REX garbage collection forces an image to be moved from one block to another.
5) DONE R4.3 - Overall stability - Identified and fixed two subtle bugs relating to interrupt handling and bank switching.
6) DONE R4.3 - Robustness for TPDD routines - major rewrite of the TPDD routines in 4.3.
7) DONE R4.3 - included choice for refresh or revert - Restore from current ram image - there is no easy way to restore from the current backup image. Solution TBD. work around is to copy the backup image to a new block, and then install that image.
8) DONE R4.3 - non-blank block recovery - it is possible that REX attempts to copy an image to a non blank block. This situation is indicitive of a problem with the system since this should never happen. If it does occur, the system gets in a deadlock condition. Solution - make sure REX has no bugs in this functionality first, but an option to "name" or "delete" the offending block would be a nice safety system.
9) DONE R4.3 - enter function displayed on line 2 - state function of <enter> for cursor item on screen somewhere - don't leave it to memory only
10) DONE R4.3 - <TAB> is included in top line now - indicate <tab> is used to toggle groups.
11) DONE R4.3 - order is now RAM ROM OS (SYS) (SYS is a superuser feature) - change group display order to avoid tabbing past OS type.
|Status||Description||Requester / Date|
|Unknown||Support import of file from frozen RAM image to the thawed RAM image. RAM images can be used in a way similar to subdirectories. Therefore it is useful to be able to retrieve files from frozen RAM images||Jhoger 08:16, 16 April 2009 (PDT)|
|Done R4.3||Suggestion: make the TAB order OptROM, RAM image, Main ROM since Main ROM switch will be significantly less used. (order is now RAM ROM OS SYS)||Jhoger 19:54, 18 April 2009 (PDT)|
|Done R4.3||Add a visual progress indicator for flash functions.||Sadolph 04:36, 19 April 2009 (PDT)|
|unknown||Support for TPDD-2, for drive 1: (0: is supported).||Sadolph 04:36, 19 April 2009 (PDT)|
nb: to put a username+datestamp just type 4 tildes ~~~~