I use it (PoOP). I also have a 43" "TV" Monitor that I display
various PDF documents on, parts of listings, and other things...
I will probably be using it on the next ALC project I am in the
process of starting as I will probably have to learn all the
64bit USER instructions.
And yes, I have the white card (s/360-20) the green, yellow, blue
and salmon cards. Plus some others.
One of the things I have to use it (ref Sum card) for is
remembering "masks" and CC stuff for different instructions. Get
away from doing it and you have to refresh your memory... sigh.
Yeah, I'm one of the younger old ones.
Regards,
Steve Thompson
On 10/20/2025 2:46 PM, Dan Greiner wrote:
We ancient fossils fondly remember the "IBM System/360 Reference Data"
(X20-1703), better known as the green card ... a 12-panel folded document that summarized
the instructions, mnemonics, operands, and hardware data structures of the original IBM
S/360. The appearance of a green card in a shirt pocket – likely behind a pocket
protector full of pens – identified the bearer as a true believer ... a programmer not to
be trifled with. Over the decades as the architecture grew from 151 instructions to well
over 1,200 in the current z/Architecture models, the green card grew into a
reference-summary booklet (of varying colors) that now exceeds 100 pages.
In this century, IBM eschewed hard copies by (a) providing these documents in a
PDF for free, and (b) charging outrageous prices prices for hard copy; then
about 10 years ago, they dropped hard copy completely. For the PoO, this was
understandable ... it now consumes over two reams of paper and costs a bundle
to ship. However, for the Reference Summary, this made the publication MUCH
less useful. (I have actually printed a copy, trimmed it down to size, taken it
to Kinko's for comb binding, and never looked at it again. )
Since all of the information in the Reference Summary can be found in the PoO –
and it seems unlikely that IBM will come to their senses and make hard copy
again – it seems ridiculous to bother producing it any more. I asked the
current editor of the documents his opinion, and he agreed that it's unlikely
that the Reference Summary is useful any more.
This seemed like a great forum to solicit informed opinions. However I do
hesitate, knowing that some will take this as an opportunity to vent their
spleen about documentation in general. Please don't. I simply wish to provide
feedback to the Systems Architecture group as to whether this document is used
in its current online-only format.
