[Leica] What does ROM do?

[InfinityDT@aol.com]

Can someone clear up a question I've been asked and can't answer even after 
calls to Leica USA and reading all the brochures?  I have a relative driving 
me nuts about some R stuff.  She wants to get a used 28-70 and 70-210 lens 
(both non-ROM and non-updatable, and all she can afford) but would like an R8 
rather than an R7 because of the 1/250 flash sync and (she says) brighter 
finder.  

So, the question is: What, at this point in time, does the ROM strip actually 
do with the R8?  All I've been able to get so far is that it tells the Metz 
flash what focal length to zoom itself to.  Are there any other functions of 
the R8 (finder displays, metering modes, etc.) that won't function without a 
ROM lens?  


Also, the Leica lens listing on their website makes reference to "ROM and 
Sensor" with respect to the 28-70 and 35-70 f4 lenses, but not any others.  
Anyone know what that's all about?

TIA
DT