Mainframe/Z-series General discussion

Mainframers and people interested in the platform, use this thread to discuss mainframes in general, or to ask any questions

Bump,
surely someone else here works with mainframes in some capacity or is interested

didn't you hear, even IBM is moving to on demand, aka the cloud, now.

That's true and i'm seeing the amount of PAAS systems increase massively, but the simple fact of the matter is that so many core applications are tied into the mainframe for most Banks/Insurance agencies that exiting the mainframe is too expensive and high risk for almost any of them

philip young by any chance?

or at least, have you seen his videos?
My question:
Are mainframes really as insecure as he makes out??

not saying how I know, but in boulder, there was an IBM server with open ports for 12 years before someone noticed, only had banking and pharma data on it, nothing important like.

Any interesting facts you can share about mf's? Is that a cooling system inside that IBM?

No but I'm aware of who he is, not that I agree with his videos
Mainframe security is strange because unlike most other systems, they come incredibly unsecure. It's up to the administrators (aka system programmers) to build the system up to scratch, however they have lots of options to secure to the system to an almost watertight level.
Firstly; mainframes generally aren't connected to the internet continually. At least where I work, when necessary the best system programmers will connect the mainframe to the internet through a series of firewalls and jump servers to download updates to programs running on the mainframe. Apart from that it's completely shut off, only interfacing with user terminals and other systems that are closer to the web in general.
Mainframes also have optional hardware modules for cryptography; I'm not a hardware engineer so I'm not gonna pretend I know how they work or what they do, but I do know that they are widely used in the industry.
The mainframe also thrives largely on security through obscurity; not many people know how to write JCL and COBOL any more, and whilst you can execute most programming languages on a MF this is usually locked down heavily.
There's loads more to talk about security and I can if you want but it's late over here and i've got a big day tomorrow

with the current state of virtual machine load balancing and performance scaling, what are the advantages of using what is essentially an analog load balancer?

other than obviously having a super cool black betty in your basement.

it seems incompatible with geo-redundancy and dependent on a core group on analysts and programmers who can hold your business decisions hostage for decades while the system is paid off

Obviously the mainframe comes almost completely unsecured and it's up to the engineers to configure it in a secure manner. In the case you're talking about the internal network team should have had at least one audit in that 12 years so it's more a matter of bad policy than anything.
There's lots of interesting facts about mainframes, I wouldn't know where to begin to be honest!
I suppose one thing is that most places will be running their workload on only 1 or 2 physical machines; these machines are then chopped down into lots of Logical PARtitions (LPARs). Where I work we have over 40, with development and live residing onthe same box.
That picture is of IBM's latest mainframe offering, the Z13. It contains all the components needed apart from storage , and yes the bit right at the bottom is a watercooling module.

They've already been doing something like that with onsite hardware. They include all the CPUs in the box but charge to unlock each one.

Modern mainframes are actual massively scalable, both immediately and for future planning. The standard mainframe box is hugely expandable, and if you still don't think it's going to perform up to scratch then it has what's called a coupling facility, essentially shared memory, to allow it to interface with other physical machines. Adding to that, mainframes are designed to run with no problems at 99.99+% CPU usage; try running a Wintel/UNIX box at that level and see if all of your processes are running correctly.
Obviously none of that's any good if you suddenly hit unexpected demand and need some more processing power immediately, which is where OOCOD (on/off capacity on demand) comes in. OOCOD is essentially where you install extra CPUs that you don't license for constant use, and instead you only activate and pay for them when you need them.
With regards to Geo-redundancy unfortunately you couldn't be further from the truth. IBM's product for data replication (GDPS) is incredibly powerful and has led to my work creating a hugely redundant model for mainframes and storage; we have 2 different sites, each with 2 'corners', running the primary workload out of just one corner in the primary datacentre; this replicates data to all of the other corners. in the case of power loss in the primary corner, we can switch over to the secondary corner. In the case of total datacentre loss, we would fail over to the secondary datacentre, where we'd still have redundancy in the 2 corners.
Obviously the system is highly dependant on specialists, but we don't just wait for a system to be paid off; we're in the process of selling 4 old mainframes back to IBM and only paying for the depreciation over their life, which is actually relatively low.

you can thank intel for that business model although ibm will be able to make it work so much better as they have contracts rather than one-off sales with perhaps some afterlicensing

so essentially even more proprietary but likely better esxi

im still learning and very sarcastic but from the actually very much thank you

also plz, my p4 is faster

Yep, if you're interested in it I'd read up on it; there's too much information for me to link here but it's a really cool field to look into!

>so essentially even more proprietary but likely better esxi
Close but no cigar, if you're thinking of a standard HyperVisor then read up on z/VM, it's essentially a hypervisor that can be run as an LPAR allowing you to run linux or any other POSIX OS.
>im still learning and very sarcastic but from the actually very much thank you
Glad to be of service
>also plz, my p4 is faster
no

and like what field is that? marketing or systems engineering? the lines are blurred because a z series 'general' is too pimp to exist

Well specifically they were talking about OOCOD so they'd be searching for that or for performance analytics in general, however the general sector would be systems engineering.
Sorry if it seems like I'm marketing for IBM; I don't work for them, but i almost exclusively work on their products!

COBOL!

logical partition as in just, the hardware controller allocates just so much hardware to create a machine space that one runs the hypervisor on which in turn allocates its own resources as it needs?

thank goodness you took all the training, since you were posting on Sup Forums i almost thought the washing was not complete

>logical partition as in just, the hardware controller allocates just so much hardware to create a machine space that one runs the hypervisor on which in turn allocates its own resources as it needs?
Essentially yeah, you allocate resources like RAM and CPU when you create the LPAR, but you can dynamically move resources around if needs be
>thank goodness you took all the training, since you were posting on Sup Forums i almost thought the washing was not complete
I'm still quite young so I've not been completely washed yet

yet here you are

JCL!

>we have 2 different sites
we have 2 different sites
2 SITES

wow great fucking redundancy

One thing about those that always bothered me is how unfinished they look inside.

freaking deserted

I thought transparent cases fell out of fashion in the 00s? Is IBM that far behind? I think the Z12 was a better look. When selling magic boxes, the inner workings should remain obfuscated.

Never mind, It looks like they do put a cool Batman facade on it.

Thinking about trying to install Hercules emulator to try out a free version of MVS. What is Turnkey?

I'd be more interested in mainframes if I could actually play with one.

I did talk with a dude from compuware, and he was saying they mostly write in asm and have some crazy awesome debugger they wrote.

He also was saying that they're starving for mainframe programmers since a lot of unis removed their programs so the job security is amazing, but training is difficult.

what actually are mainframes these days?
in the past they were basically a computer with way more compute and resources than regular servers pcs to allow for heavy continuous workloads to be run

are they still essentially that? if so, what's the point when we have clustering or distributed compute paradigms these days? cost of the those two would probably be much lower also

legacy systems?

Essentially they're super clusters wrapped in a single package with large internal bandwidths that you wouldn't get with an x86_64 based cluster

I named my desktop littleiron :p

ibm has a competition every year where they give you access to one
master the mainframe it's called i think