Why are we still using Mainframes? Do we have any alternatives? How easy is it to migrate?
Why are we still using Mainframes?
1–10 of 19 posts
Re: Why are we still using Mainframes?
#2I think it is because it is the easiest/cheapest way to reliably handle a fuckton of transactions. So it's great for a bank. I can't think of any other use cases though.
Re: Why are we still using Mainframes?
#3Legacy code bases.
I wonder how much of my 1986 code is still in use.
Re: Why are we still using Mainframes?
#4>> Do we have any alternatives? How easy is it to migrate?
Oh god, no, don't even think about it. It's hard enough migrating away from a code base in Java, written 10 years ago and that runs on pretty much anything. Imagine how hard it is to migrate from a code base written in languages known best by engineers in retirement, that only runs on extremely expensive supercomputers made by almost a single company (IBM).
But the worse thing is that you can't just pull the guts out of the software that runs all the transactions of huge financial organisations. You can't just throw a switch and stop all financial activity in a big bank, while you swap a new system in place, because every second of downtime costs millions. Millions! Who is going to take the responsibility for that?
So change never happens because nobody dares make it. One day mainframes will outlive the last people who can program them competently and then we'll all be in trouble.
Re: Why are we still using Mainframes?
#5>> Do we have any alternatives? How easy is it to migrate? Oh god, no, don't even think about it. It's hard enough migrating away from a code base in Java, written 10 years ago and that runs on pretty much anything. Imagine how hard it is to migrate from a code base written in languages known best by engineers in retirement, that only runs on extremely expensive supercomputers made by almost a single company (IBM). B…
It's been done. Design and implement a replacement system, run it in parallel for a meaningful timeframe, then switch over. You need a parallel implementation simply as a "hot backup" in case your primary system fails for whatever reason anyway, and it's easier to implement real-time redundancy in current systems anyway. (This was the niche that Tandem Computers served.)
I think most mainframes in the USA are used to run old legacy systems that will be needed not much longer (or that's the plan, anyway), like shop-order control for old weapons systems -- tasks for which no replacement system would be necessary because the need ends with the project.
Re: Why are we still using Mainframes?
#6Legacy code bases. I wonder how much of my 1986 code is still in use.
Out of curiosity: what did you write in the 80s?
Re: Why are we still using Mainframes?
#7In my experience, mainframes tend to be used where functional requirements are very slow moving and reliability trumps flexibility.
I don't know of any case where a mainframe couldn't, in principle, be replaced by a server farm. However, maintaining a sufficiently reliable and secure server farm is a specialist job too so the benefits aren't always clear cut.
Ease of migration is really down to what the mainframe is doing and for how long. In practice, they tend to be in place for a number of years in hub-type roles e.g. general ledgers, payment systems. That sort of thing. The effect is that extricating them is extremely complex and expensive.
However, these issues aren't really limited to mainframes. We have the same problems with trying to extricate Sparc Solaris applications. We generally want to replace them with Lintel as we use them in most applications. But doing so is horribly complicated as they're embedded in byzantine flows that few understand and the systems often assume a level of hardware reliability that commodity boxes don't have.
Re: Why are we still using Mainframes?
#8In my experience, mainframes tend to be used where functional requirements are very slow moving and reliability trumps flexibility. I don't know of any case where a mainframe couldn't, in principle, be replaced by a server farm. However, maintaining a sufficiently reliable and secure server farm is a specialist job too so the benefits aren't always clear cut. Ease of migration is really down to what the mainframe is…
Similarly this is why, in some places, people report having "that old XP machine running in the closet" because is really important to them and they have no path forward (it doesn't support > XP, it's actually too vital - though that seems like an odd reason not to update, etc.).
You could replace these things with something newer but the concerns by various parties can outweigh the willingness to fight and you probably don't want to be on the receiving end of "I told you so".
Re: Why are we still using Mainframes?
#9In my experience, mainframes tend to be used where functional requirements are very slow moving and reliability trumps flexibility. I don't know of any case where a mainframe couldn't, in principle, be replaced by a server farm. However, maintaining a sufficiently reliable and secure server farm is a specialist job too so the benefits aren't always clear cut. Ease of migration is really down to what the mainframe is…
Similarly this is why, in some places, people report having "that old XP machine running in the closet" because is really important to them and they have no path forward (it doesn't support > XP, it's actually too vital - though that seems like an odd reason not to update, etc.). You could replace these things with something newer but the concerns by various parties can outweigh the willingness to fight and you proba…
The XP factor is another good reason why people stay on mainframes. They tend to be supported forever, or as near as dammit. You don't get that (quite reasonably) with consumer grade software and hardware.