[skissane]

Is someone in the US government really still using an IBM 7074? Really? I'm shocked. How could that possibly be cost-effective?

Actually, this blog post makes the story clearer:

http://nikhilism.com/post/2016/systems-we-love/

It isn't a physical IBM 7074.

When it came time to migrate from 7074 to S/360, rather than rewriting their 7074 software, they just wrote a 7074 emulator for S/360. And, it sounds like, they are still running their 7074 software, under their 7074 emulator, most likely on a recent z/Architecture mainframe.

The article makes it sound like people still use "1960s mainframes" when I very much doubt anyone is still running 1960s hardware in production. People use modern machines–modern IBM mainframes, which are multicore 64-bit processors–or other mainframe vendors such as Unisys or Fujitsu use mainly I believe x86-64 running Linux running a software emulator for the old mainframe CPU.

A lot of legacy, sure, but I think this article makes it sound even more legacy than it really is.

[Animats]

The picture of an IBM 7074 is from Wikipedia.

IBM offered 7074 emulation as a standard IBM System/360 product.[1] On an S/360, it required some special hardware support. In 1972, IBM gave users a free IBM 7074 emulator, software only, for System/370 machines.[2] They may still be running that program on a Z-series mainframe.

[1] http://bitsavers.trailing-edge.com/pdf/ibm/370/compatibility...

[2] https://books.google.com/books?id=p5zVQgaQ-N0C&pg=PA11

[YeGoblynQueenne]

It's possible Ms Belotti and her team didn't realise they were working with an emulator. Mainframes being what they are, the programmers were probably never in the same room as the machines they were progamming, and it does take a bit of digging to figure out that the architecture you see before your eyes is emulated on another machine (like in "The Story of Mel").

Still, even the blog post you link to doesn't make it absolutely clear that java was running on an emulated s/370. It says that the decision was made to emulate the older architecutre rather than rewrite the old programs, but then it goes on to say "These are still operational". Does it mean the old programs? Or the old machines? It's hard to say.

As to how unlikely it is to see a very old machine still in use, instead of one made in more recent times, last year I talked to an engineer who claimed he had seen a PDP still in operation in some transport company if memory serves.

[abakker]

I believe (a coworker of mine worked on S/360) that all the old software can be effectively run through emulators on the current system z. The feeling was that once you had done the development and testing of an older system, IBM was never going to force you to rewrite your code. As a result, the upgrades were pretty seamless over the years. Many of those customers never had to upgrade and never had a reason to.

[vidarh]

PDP-10 was discontinued in 1983, but PDP-11 wasn't discontinued until 1997, with third-parties continuing to sell parts, so it's really not that unlikely to come across PDPs, depending on which line.

[1812Overture]

I 100% buy they're using 1960s hardware. I've talked to some people who had to spend half their day on ebay trawling for parts to keep their ancient systems running. I've personally worked with medical offices still using 1970s hardware, it's not that rare. Many places have an "if it ain't broke don't fix it" attitude.

[wwweston]

And it's an open question whether or not that attitude is better. A day or two of office admin time every 3-6 months is quite possibly more cost effective than hiring one of us for weeks/months/years to create a new system...

[whyileft]

Especially in a doctor's office where artificial supply restrictions on degrees and licensing give them little or no competition for clients.

[tomcam]

I/O speed reported in the article seemed highly unlikely for mag tape

[floatboth]

"a different group of mainframes would run an automated job that would harvest that data from the magnetic tape and load them up into more traditional databases"

[kpil]

I think most of it is highly unlikely...

[mbellotti]

> A lot of legacy, sure, but I think this article makes it sound even more legacy than it really is.

Indeed. The point of the talk was that 1) legacy is often assumed to be bad not for any real technical reasons but just because it is legacy and 2) a lot of what was being presented as legacy wasn't even legacy. Their OS 2200 version was actually newer than the Oracle DB they were using on the "modern" side of the stack.

[nickpsecurity]

You might enjoy this article given the kind of work you do:

http://www.pcworld.com/article/249951/computers/if-it-aint-b...

You've probably seen plenty of crazy stuff in legacy systems but I'm hoping at least one surprises you. Maybe the first one. :)

[wolf550e]

I know of an S/360 assembly code base that (as of a decade ago), still ran code that assumed 24 bit address space and used 31 bit pointers with tags stuffed in the unused 7 bits. So it had to run in the lowest 16MB of memory, on a 64-bit machine. I don't think they had the budget to rewrite that subsystem to fix it. So yes, new hardware, but some of the legacy problems in the software run very deep.

[fennecfoxen]

They're often virtualized but don't underestimate mainframe persistence.

At my last job as a consultant someone made https://github.com/manheim/antimony for testing IBM TN5250 mainframe screens in Ruby - it's like Selenium but even more brittle. :>

[cle]

It's "cost effective" because "cost effectiveness" is not as objective as we think, once we start considering things like risk tolerance.

[kevin_thibedeau]

ClearPath Dorado still had a Univac on a chip until 2015. This is actual hardware, not just software emulation.

[acqq]

Yes. And they never accessed 1960 IBM Mainframe at all with their software. The title is probably intentionally misleading.

And the one they actually accessed and received query results in 6 milliseconds was introduced in 2008, not so old and slow:

https://www.app5.unisys.com/offerings/ClearPathConnection/st...

"Single image performance range of 300 MIPS at the entry level and maximum single image performance of approximately 5,700 MIPS (32 processor system)."

"An expanded memory subsystem supports larger memory capabilities and offers memory configurations that include the ability to expand up to 4GW per cell and up to 32GW for a maximum eight-cell system."

[kchoudhu]

Mazal tov, that's containerization...from the 1970s.

Everything old is new again. I love our profession.

[facepalm]

I was going to ask if they couldn't just replace the hardware with emulators :-)

[kevin_thibedeau]

Does ext4 journal mode not journal everything?