04 Jun 2003, 05:17, Leonard Erickson (1:105/50), wrote to JEAN PARROT:

Hi Leonard.

 JP>> Are you not going against the grain of the wider opinions here
 JP>> ? I got back into the box here to change all this to the HDs on
 JP>> one IDE and the CDs on tother because all were suggesting that
 JP>> it was the way to have it when before I had it the way you now
 JP>> suggest.   Strange !

 LE> Transfers between drives one the same IDE cable have to take 
 LE> turns. Read from one drive into a buffer on the card, then write from
 LE> that buffer to the other drive. They have to take turns using the 
 LE> cable.

 LE> If they are on different channels, then you can read from one and 
 LE> write to the other at the same time. 

Not quite Leonard.  Regardless of multitasking, or whatever people want to
call it from day to day, the CPU can only run ONE task at a time, period!

There is no way a CPU can read from one drive and write to another at the
same time, or even make it _look_ like it is.  You will NEVER see both HD
lights on at the same time.

In the case of BOTH drives on the same channel (cable), The CPU has to
first select the channel, then read to main RAM, then write that RAM to the
second drive on that same channel.

In the case of the drives on separate cables (channels), the CPU has to
select the _read_ drive, read the data into main RAM, then select the
_write_ channel, then write that data to the second drive, and repeat until
the copy operation is completed.

By having both drives on the same channel, the CPU has to perform two less
_select_ options per data block transfer, as that one channel simply
remains selected.

For copying a few files, it makes no significant difference, but when you
are constantly copying complete 120G drives, the time difference is VERY
noticible.

All in all, HOW you use the computer will determine what gets connected
where for optimum results.


     Good luck...  M.

--- Msged/386 TE 06 (pre)