REX Release 4.9

Supported Models

• Model 100 and Tandy 102 with either REX or REX2
• Tandy 200 with REX
• NEC PC-8201 with REX3

M100 note

 In Europe and UK, and probably elsewhere, there are newer versions of M100 that have different boards.
 Model numbers are 26-3801B and 26-3802B.
 It isn't clear if REX works in those systems; until I can verify, assume REX does not work in anything
 but a USA/Canada equivalent M100 (meaning it has a Modem, and the custom ROM pinout).
 ***UPDATE*** confirmed that UK M100s need to use a US main ROM image.  Options include getting a 
 new main ROM burned using a known good binary image, or wiring your computer up using Main ROM Management feature.

New Features

• QUAD support - has been removed from release 4.9 as of revision 254.
• Y2K Fix - REX now automatically fixes the year displayed in MENU.
• PC-8201 support (including TAB key in addition to SHIFT-F5 to bank-switch, like T200)
• Multi-bank support - see description below
• Quick Menu features - see description below
• REX status indicator in MENU - the active Option ROM (for each bank) is indicated in the display

REX Functionality Overview

REX remains similar to release 4.8, but several major new capabilities have been added. The differences are outlined below.

Quick Menu Features

For commonly used functions, now some shortcut keys are available in MENU. This avoids the need to start REXMGR to perform simple operations like ROM switching and backing up your RAM.

Summary of commands:

• <CNTL-O>: Switch Option ROM - REX will display available Option ROMs, and the user can use arrow keys to move the cursor to the desired selection. <ENTER> to activate the new selection and start that ROM. <ESC> to exit. The Active Option ROM is indicated with a *.
• <CNTL-B>: Back up RAM - REX will prompt the user to confirm, and if confirmed will copy RAM to the active RAM image, performing a backup.
• <CNTL-R>: Restore RAM - REX will prompt the user to confirm, and if confirmed will copy the active RAM image to RAM, performing a restore.
• <CNTL-X>: Hooks removal - REX will prompt the user to confirm, and if confirmed will remove all hooks relating to REXMGR from the laptop operating system, effectively disabling REX. REXMGR remains in the MENU, so REX can be easily reinstalled. Also, the Active Option ROM is accessible using the usual ROM start procedures. This feature is useful when it is desired to run the Option ROM without REX active.

Multi-Bank Operation

Unlike Model 100 and Tandy 102, multi-bank machines PC-8201, T200 have an advantage in that the user has up to 3 distinct memory spaces to work with. Prior to release 4.9, all of those banks would have the same Option ROM active. In Release 4.9, multi-bank machines now may access unique active RAM images and active OPTION ROM images on a per-bank basis. For example, TS-DOS, UR-2 and R2C can be assigned to each bank, and each bank can have an associated RAM image. This means the user can simply TAB between spaces and quickly use different Option ROMs, and each RAM space can be backed up separately.

In REX Manager, images are marked with '*' next to the name when that image is ACTIVE in the current BANK. Images that are ACTIVE in OTHER BANKS are marked with '#'. Pressing B or b in REX Manager will indicate the BANK associated with an image, as well as the block number the image occupies in REX flash memory.

Y2K Fix

Prior to Release 4.9, users wanting a fix for Y2K would have needed to make use of Main ROM Replacement via REX. This requires a hardware modification. Now, a Y2K patch is automatically applied when in MENU.

Rebuilding REX

 In order to use revision 254, users must do a complete rebuild of their REX.

All rebuilds to REX are `clean sweep` upgrades, meaning you must save off all important stored RAM images to a TPDD device. After the upgrade, you can re-load your important RAM and OPTROM images into REX. The FLASH memory in REX is completely wiped.

Please see the section below for specific software release bundles.

What you need

• for M100 or T102: RF149.CO, RXF149.BR, TSD100.BX
• for T200: RF249.CO, RXF249.BR, TSD200.BX
• for PC-8201: RFN49.CO, RXFN49.BR, TSDNEC.BX
• your favorite TPDD device connected to the laptop

Place the files in the root directory of your TPDD device for loading.

In order to make a "clean sweep" and make sure that no issues with older software, for the initial installation of 4.9 we take the approach of wiping the old directory, and all the flash contents (from block 6-31; the user space) and initialize things to default.

A note about Rom Replacement - if you are using this feature then you know that your main OS roms are stored in block 2-5. Those blocks are not erased, and they stay in place and operational the whole time. My three test machines are all running with REX based main roms.

Step 1

So then, the first thing to do is for you to 'Save' all your existing RAM and OPTROM images 
(the ones that you both want to keep and are not already stored on a PC somewhere) out of REX 
and onto your favorite TPDD device.  Please go through your saved images, decide what you want 
to save and use again, and get them out of REX.  After we install R4.9, all those images will 
be wiped.  You will have to reload anything you need.

Step 2

Load the rebuild tool:  Load into RAM the RFx49.CO file using the TPDD device.  
You will need to CLEAR0,55000 to run the program.  But, don't run it yet.

Step 3

Remove REX software from the laptop.   This is an easy step - just go into REXMGR and press F7 
(or SHIFT-F4 in PC-8201/8300)to DEINstall REX software.  
You should find yourself at MENU with RFx49.CO in the directory of the laptop.

Step 4

Issue the BASIC command CLEAR0,55000.  Exit BASIC and run RFx49.CO from Menu.  
RFx49.CO will do the necessary steps of erasing blocks, loading the REX software, 
copying it to backup block 1, and then loading TS-DOS into block 8.

Step 5

Once RFx49.CO completes, you should be able to start REXMGR.  Power cycle the laptop.  
Cold restart the machine to clean out any funny memory stuff.  Enter BASIC and type either

CALL63012 (M100/T102)
CALL61167,2 (T200)
EXEC62394 (PC-8201)

Voila! You should see REXMGR in the MENU, and you should see the fancy new OPTROM indicator in the top right corner. You are now running release 4.9!!!!

REX Release 4.9 Upgrade Packages

The following files may be downloaded and used to upgrade your REX from an older release to R4.9 revision 260. Because the directory structure is new in release 4.9, users must do a full rebuild when on 4.8 or older. Remember a full rebuild will completely wipe and rebuild your REX so save important data to a TPDD device!

These are the checksums for revision 260:

  M100 = DF79
  T200 = 18BA
  NEC = 3B3E

If your checksum (by pressing I) is not this, then you should upgrade.

Status	Release	Model	Description	File	Revision
Beta	4.9	M100/T102	REX Release 4.9 Rebuild Package	R49_M100T102_260_rebuild	260
Beta	4.9	T200	REX Release 4.9 Rebuild Package	R49_T200_260_rebuild	260
Beta	4.9	NEC	REX Release 4.9 Rebuild Package	R49_NEC_260_rebuild	260

The following files may be downloaded and used to upgrade your REX from an earlier R4.9 to revision 260. These files are update only; directory and flash contents should stay the same after the update to REXROM.

Status	Release	Model	Description	File	Revision
Beta	4.9	M100/T102	REX Release 4.9 Update Package	R49_M100T102_260_update	260
Beta	4.9	T200	REX Release 4.9 Update Package	R49_T200_260_update	260
Beta	4.9	NEC	REX Release 4.9 Update Package	R49_NEC_260_update	260

About Main ROM Management

Please see the main REX wiki page for a description of this feature - how to prepare a ROM image, how to modify the hardware, and how to load REX with images.