A Fresh Look at IBM 3270 Information Display System(rs-online.com)
rs-online.com
A Fresh Look at IBM 3270 Information Display System
https://www.rs-online.com/designspark/a-fresh-look-at-ibm-3270-information-display-system
24 comments
IBM's CICS has web support https://www.ibm.com/docs/en/cics-ts/5.6.0?topic=fundamentals...
It does turn out that 3270 streams and web forms are similar. Transmit a form, wait for the user to fill in the fields on the form, then receive the fields when the user submits it. It is how a mainframe in the 1970s/80s can support 100s of terminals, despite being small by modern standards.
It does turn out that 3270 streams and web forms are similar. Transmit a form, wait for the user to fill in the fields on the form, then receive the fields when the user submits it. It is how a mainframe in the 1970s/80s can support 100s of terminals, despite being small by modern standards.
That is a beautiful piece of industrial design.
IBM terminals were the original stateless clients. :)
I had a PS/2 Portable 70 for a while. It was a luggable Microchannel PC with a orange plasma display. Going through airports with it was a hassle as it didn't have batteries - I would have to find an outlet to power it on for airport security inspection.
I had a PS/2 Portable 70 for a while. It was a luggable Microchannel PC with a orange plasma display. Going through airports with it was a hassle as it didn't have batteries - I would have to find an outlet to power it on for airport security inspection.
Articles like this always paint a rosy picture of the 3270 but consider the limitations. Async style updates as commonly found on a VT designed program were tricky.
Now admittedly my own experience with the 3270 was through about three layers of obtuse IBM operating systems. Perhaps if I sat down with a 3270 and a bare OS I would consider them differently, but I always found them terribly limiting compared to a VT. More efficient sure, but much harder/impossible to do cool stuff on.
source: I was a night shift tape monkey for a IBM place for a few years. A fair amount of down time, access to a full set of manuals and an understanding boss meant I was doing more hacking on production mainframes than I probably should have been.
Now admittedly my own experience with the 3270 was through about three layers of obtuse IBM operating systems. Perhaps if I sat down with a 3270 and a bare OS I would consider them differently, but I always found them terribly limiting compared to a VT. More efficient sure, but much harder/impossible to do cool stuff on.
source: I was a night shift tape monkey for a IBM place for a few years. A fair amount of down time, access to a full set of manuals and an understanding boss meant I was doing more hacking on production mainframes than I probably should have been.
They optimized for different things. The instant responsiveness of the 3270 vs. the VT at Xbps for local editing was nice. You could do async updates and even async input (via polling) as well though there was this annoying thing where the input could clash with the output and you'd get this weird icon that you had to clear (my brain is iffy on the details) e.g. when you hit a PF key while the display is updating. I think there was some workaround. I wrote some games that ran on the 3279 in an async mode (using some utilities a friend of mine built for that).
My finest work on the 3270 was an analog clock screensaver.
It was simultaneously the hardest and most pointless thing I have ever written.
Our interface to the mainframe was CMS/VSE on Z-OS. We never touched Z-OS and I was a little afraid to try, but on CMS there was REXX installed as a scripting language and I built an immediate mode character update library for it, mainly so I could sort of treat it like a VT instead of abusing the text editor(XEDIT if I remember correctly) as a ui toolkit like every other script there did, I never did figure out async keyboard reads, so probably had to poll like you said) and promptly did the first thing you do when you have access to an immediate mode text screen in the early 2000's, made a matrix screen saver. (no games because of the lack of async keyboard reads, so screen savers it was)
Anyhow the hard part, CMS REXX had no trig library, how was I going to do the hands on my analog clock without a trig library? So I smuggled in some printouts from the nist algorithm database(what an amazing website) on how to calculate sin, only to discover that REXX also had no exponent function, so the next night I smuggled in some printouts of how to calculate that. and some days later was the proud owner of an analog clock screen saver and perhaps the slowest most inefficient exponential and trig libraries to be found on CMS/REXX
I wish I could have saved the source, but... it was on a mainframe and really, I was just there to shuffle the tapes around, when my boss tried to warn me off of writing scripts I convinced him it was to help make our tape duties more productive, and for the most part it was.
It was simultaneously the hardest and most pointless thing I have ever written.
Our interface to the mainframe was CMS/VSE on Z-OS. We never touched Z-OS and I was a little afraid to try, but on CMS there was REXX installed as a scripting language and I built an immediate mode character update library for it, mainly so I could sort of treat it like a VT instead of abusing the text editor(XEDIT if I remember correctly) as a ui toolkit like every other script there did, I never did figure out async keyboard reads, so probably had to poll like you said) and promptly did the first thing you do when you have access to an immediate mode text screen in the early 2000's, made a matrix screen saver. (no games because of the lack of async keyboard reads, so screen savers it was)
Anyhow the hard part, CMS REXX had no trig library, how was I going to do the hands on my analog clock without a trig library? So I smuggled in some printouts from the nist algorithm database(what an amazing website) on how to calculate sin, only to discover that REXX also had no exponent function, so the next night I smuggled in some printouts of how to calculate that. and some days later was the proud owner of an analog clock screen saver and perhaps the slowest most inefficient exponential and trig libraries to be found on CMS/REXX
I wish I could have saved the source, but... it was on a mainframe and really, I was just there to shuffle the tapes around, when my boss tried to warn me off of writing scripts I convinced him it was to help make our tape duties more productive, and for the most part it was.
I'll give you props for studying the systems manuals and not the handmade Adventure maps drawn on green-bar paper and hidden behind the back of the last 3270 at the far end of the row of tape request consoles.
I was on the DEC side with an amber VT220 and always thought it was cool that the 3270 could scream "mount me now dammit!" in flashing red block letters while the operators weren't sure if they should drop the keys or pick up the lantern.
I was on the DEC side with an amber VT220 and always thought it was cool that the 3270 could scream "mount me now dammit!" in flashing red block letters while the operators weren't sure if they should drop the keys or pick up the lantern.
What sort of data were you work with back then? Bank stuff?
It was a mid sized mail order company, they had invested early with computers, and not changed much since. It was a very strange mix of odd old computer systems. An IBM mainframe batch processing backend with sco unix on the front end using pick databases as a sort of vertically integrated database and terminal ui.
When hired I had just missed the retirement of some sort of lockheed minicomputer they had used in the call center, which I would have loved to see. It was a very odd environment.
When hired I had just missed the retirement of some sort of lockheed minicomputer they had used in the call center, which I would have loved to see. It was a very odd environment.
The 80×24 display of the IBM 3270 is the reason that terminal windows nowadays are typically 80×24 (or 25 lines because the IBM PC added an extra line). IBM dominated the CRT terminal market in the mid-1970s, so other manufacturers were mostly forced to 80×24 in order to be compatible. (And of course the IBM 3270 had 80 columns for compatibility with punch cards.)
Hey, based on the picture, I used one of those 3179 models for about 6-7 years until my company replaced it with a desktop PC running terminal emulation software.
Years later, probably around 2003, when desktop apps started getting replaced by web apps (at least at my job), I remember making that connection between web browsers and 3270s. In the 1990s, clients got very fat (think powerbuilder), but then in the late 1990s and early 2000s much of the fat went to the server-side and the web browser became the thin(ish) client. The web browser was sort of acting as a block device (like the 3270) in the sense that the end-user filled data into fields and then sent the whole thing at once by hitting some button.
With Web 2.0, the client started to put on weight again. Then with mobile apps, the fat client was back, baby! It just keeps cycling.
Years later, probably around 2003, when desktop apps started getting replaced by web apps (at least at my job), I remember making that connection between web browsers and 3270s. In the 1990s, clients got very fat (think powerbuilder), but then in the late 1990s and early 2000s much of the fat went to the server-side and the web browser became the thin(ish) client. The web browser was sort of acting as a block device (like the 3270) in the sense that the end-user filled data into fields and then sent the whole thing at once by hitting some button.
With Web 2.0, the client started to put on weight again. Then with mobile apps, the fat client was back, baby! It just keeps cycling.
the 'wheel of reincarnation' paper: http://cva.stanford.edu/classes/cs99s/papers/myer-sutherland...
I wonder when thin clients will come back into vogue again.
I've considered the BLIT to be the platonic ideal, a seamless environment there local or remote behaved the same, looked the same and acted the same - I guess the modern equivalent to that would be Citrix applications - but thats still not as seamless.
I've considered the BLIT to be the platonic ideal, a seamless environment there local or remote behaved the same, looked the same and acted the same - I guess the modern equivalent to that would be Citrix applications - but thats still not as seamless.
The IBM 3270 display family was amazing for its time - a character-oriented, block-mode terminal that supported light pens and APL keyboards in the '70s, as well as color graphics and a plasma display that supported four 80x24 logical screens in the early 80's. https://en.wikipedia.org/wiki/IBM_3270
I used to use 3270-based stuff at IBM back in the mid-2000s, when I did tech support for their EPOS systems.
They had some hyper janky Windows XP Citrix client that ran 3270 terminals that kind of half-worked on some server somewhere, that then talked to the Big Iron. When it didn't work (it frequently didn't) it meant we got a lot of coffee breaks, so not the worst in the world.
They had some hyper janky Windows XP Citrix client that ran 3270 terminals that kind of half-worked on some server somewhere, that then talked to the Big Iron. When it didn't work (it frequently didn't) it meant we got a lot of coffee breaks, so not the worst in the world.
The year was 1978. A young engineer, just out of school with a still-warm BSEE degree, is working at his new job where programming was performed using punch cards or over the phone line with a acoustically coupled modem. After 3 or so months, the company has purchased these 3270 displays with keyboards and installed them in offices. Our junior engineer is assigned one of these. After just a few moments of use, it becomes exceedingly apparent that these are of a new class of technology, indeed, making life at work ever so much more pleasant and productive. Now retired, our engineer still remembers these quite fondly. Even more so, he remembers the keyboard. How solid it felt and the wonderful tactile feedback when pressing the keys. He might even say that it was the best keyboard that he ever used.
Despite all the years using their services I had no idea RS has a tech blog!
Reminder that the X11 based x3270 client can be used to communicate with mainframes, including the "Hercules" IBM mainframe emulator that you can run on Linux/Windows/MacOS .
The terminal client program named "x3270 emulator"?
We were the envy of the mainframe folks, since we used x3270 under X/Windows and got to adjust the size, rows and colours. While they were stuck with the desktop consuming old massive terminals. Of course this was only after the mainframe sprouted tcp/ip connections.
Ancient history, but worked at a financial firm which ran Windows for Workgroups with the DLC protocol (so it wasn't eating the 640KB) over token ring, and some quite expensive do-it-all terminal software. Some of the old heads still had a 3270 in their office.
The 3290 was like a 4 split tmux session, it is such a beautiful device (https://ifdesign.com/en/winner-ranking/project/ibm-3290-info...). Perfect keyboard, plasma contrast and the right text color for long sessions. My understanding is they outlived themselves with long service in air traffic control (supplementing vector/raster displays), financial markets, and software development. Once upon a time people seemed to really care about doing things well.