This directory contains a repository of ROM images, as BINARY files.

Please note that these ROMs contain software which may be subject to
copyright.  They are provided here as a convenience to collectors of
classic computers, for use only in repairing machines and peripherals.

They are not here for free upgrades, and any misuse may result in
them going away.  If you are the owner of the copyright on any of
these images, and wish them to be removed, please contact me
(pete at dunnington dot u hyphen net dot com).

Contributions of additional PDP-11 ROM images are welcome.  See the
file "Wanted!" for images I'd especially like to get.  See the file
"ROMlist" for a description of each image.

If you download any of these images, make sure you do so in binary
mode, not text.  The size of each ROM is an exact power of two; if
the file you end up with after download is not exactly right, your
browser scrambled it.

DEC ROM part numbers all begin with "23-".
The next three digits+letter+digit are the ROM number, eg "123E2"
In some parts lists, numbers are shown with a trailing "-00".
However, my parts microfiches show hundreds of ROM numbers, and only
about eight have digits other than "-00" so in general it's redundant.

The final letter+digit gives the general ROM type and size:

A indicates 4-bit bipolar PROM
F indicates 4-bit bipolar PROM
D ?? same as E?  (mine are MOS EPROMs)
E indicates 8-bit MOS EPROM (or occasionally a masked ROM)
J indicates a PAL or HAL
K indicates a registered PAL
L ??
U ??

A9 means   512 x 4 16-pin, eg 82S131, MMI6306, 75S171, 27S13 etc
F1 means  1024 x 4 18-pin, eg 82S137, 24S41, MMI6353, 27S573, 27S33, etc
E2 means  2048 bytes, eg a 2716
E3 means  4096 bytes, eg a 2732
E4 means  8192 bytes, eg a 2764 or MCM68766
E5 means 16384 bytes, eg a 27128
E6 means 32768 bytes, eg a 27256
E7 means 65536 bytes, eg a 27512
E8 means  128K bytes or  64K x 16, eg a 27C210
E9 means  256K bytes or 128K x 16