If you only use the drive for Sun hardware and/or if you do not have a computer with the proper PROM revision, modifying the drive is the easiest route. To make shipping drives for multiple vendors easy, Toshiba has two connectors on the back of the drive's circuit board.

To modify the drive for 2048 bytes block size, take a razor blade and cut the solder connecting the leads for each. To use the drive with both a PC and a Sun, you will need to solder together a simple switch.

A pair of caveats:

• Toshiba does not recognize or support this modification
• this invalidates your warranty, so make sure the drive works before you do it. None of these drives are most likely under warranty any longer, so this shouldn't be a concern :-)

Here is the patch:

The 3301/3401/4101 both have two jumper pads on the accessible back part of the circuit board. The pads are solder joints shaped like two sets of opposing half-moons.

On the drives shipped to the PC market, both pairs are jumpered. On drives shipped to Sun, [both] of the pairs is cut. Drives shipped to SGI have a different combination cut. The two pad pairs are labeled 0 and 1. The combinations are:

0       1       Selected Version
-----------------------------------------
Connect Connect Toshiba Standard Version
Connect Cut     512 Byte Block Length
Cut     Connect SGI Version
Cut     Cut     Intergraph/Sun Micro

You will quickly ascertain that once you cut a trace, your drive is then altered for use on a different system. The only way to go back and forth is to cut both traces and wire the pads to two simple switches so you can set any of the four combinations as will. "

[The procedure came originally from the Sun Managers mailing list. Copy courtesy: bwright@world.std.com (Barton Wright)]

Here is a slighly more graphical version:

"Cut the pattern(between 2 pads, ``0'' and ``1'') near ID select jumpers, then you can use the drive for sun.

   0 v--- cut here
  -(|-|)-
  -(|-|)-
   1 ^--- cut here"

[Courtesy: futoshi@sra.co.jp (Futoshi Miyamori)]

Once you have done this, your drive will use the Sun 512 byte format. You will be able to boot from and mount CD's without any problems. You will, however, have to deal with the "unrecognized vendor" problem; only Hitachi and Sony are listed in the PROMs, so the machine will enter a brief xenophobic mode that is completely harmless; aside from a console message you should have no errors. Here is an example:

"Jan 12 22:01:40 sparky vmunix: sr0: Unrecongized Vendor 'TOSHIBA ', product 
		'CD-ROM XM-3301TA'sr0 at esp0 target 6 lun 0"

[example courtesy thad@cup.portal.com (Thad P Floryan); information from others who also had and diagnosed the vendor problem]