TDD1 DOSes With TDD2? Yes, but...
---------------------------------

Power-Disk (Acroatix) and Disk Power (UltraSoft) from the first model of 
the Tandy Disk Drive (TDD1) are compatible with the new Tandy Disk Drive 2 
(TDD2) except for an inherent limitation on the number of files both 
programs will allow.

While both programs will command the TDD2 to format for 200K, and will load
and save up to 200K as a single, "unpartitioned" disk, both programs limit 
you to a maximum of 40 files. 

If your ordinarily produce files of 5K or larger, you'll never notice this 
limitation, and you won't need a new DOS to operate all the functions of 
the old DOS and TDD2. However, with many short programs, such as the SIG 
file/disk management programs, you'll have to use the Tandy Floppy.CO 
program in order to put 80 files on a disk...and then, you'll have to use 
Floppy. CO to read those in "Bank 1"...at least until these 2 companies 
modify their programs to display more than 40 files.

Then, there's an insidious point about Disk Power: it's copy protection 
scheme prevents you from loading it into your computer with a TDD2 -- it 
MUST be loaded with a TDD1. Then it will operate a TDD2.


Power Drain Differences: TDD2 vs TDD1
-------------------------------------

The surge current drain of the TDD2 when turned on is greater than that of 
the TDD1. That means potential problems when attempting to power both the 
TDD2 and the Model 100/102/200 from the standard 26-3804 6-volt power 
adapter. 

The problem is complicated by the auto power-down feature; when it takes 
over, and you have to switch the drive off and on again, the surge demand 
of the TDD2 will power-off the computer...which can make for a lock-up and/
or cold start if the drive program begins to run.

Fortunately, in my case, the built-in one-second delay of the motor startup
saved me -- the computer shut down before the machine language Floppy CO 
program began to run.

Do not try going to a higher-current wall transformer to beat this problem 
-- many of those transformers put out as much as 10-11 volts when lightly 
loaded. The transformer supplied with the TTX puts out almost 8 volts -- 
safe enough, but possibly dangerous to power other accessories simultaneous
with the printer -- the surge demand of the printer is very high, too.

Best solution: use a 4-amp Yuasa battery (NP4-W) like the one Denny Thomas 
always preaches about. That can handle everything you might hang off it.