Mainframes and servers

Louiseuk25

Hi,

For one of my modules of accountancy I have to have a general level of Informations systems. Can anyone give me the basic difference between a mainframe and a server please?

Thanks

seaweasel

Google and Wikipedia are your friends.

A mainframe is a specific class of computer system whereas server is a wider term. It can refer to specific hardware, however any computer can be a server if suitable software is installed. A server pretty much does what the term suggests, it provides other computers with services, which can include (although there are hundreds of uses) serving web pages, File Transfer Protocol, Telnet, eMail, etc etc. Most computers can act as a server with desktop operating systems, however most commercial servers use an OS suited to the task, such as UNIX and Linux variants secured and set up for specific services, Mac OSX Server, Windows Server etc.

albertross_2

Gross oversimplification, but..

Mainframes tend to do the work, number crunching etc, and have dumb terminals (or PC's with a terminal app) attached to see the results, and control it.

Whereas servers tend to store the data, but not do much of the work, the majority of the processing is done on the client (a PC).

Louiseuk25

Thanks both, I did try wikipiedia but don't really have the knowledge to pull out the relevant bits to see the parallel differences iykwim.

my text has that client-servers have disadvantages:
-it is cheaper to 'tweak' a mainframe
-less easy to control than a mainframe

is this because all of the 'work' is done in one place on (rather than having to tweak or control lots of clients)?

seaweasel

Hmm, not sure I'd agree. You're not doing anything to the clients when making changes to a server, that point doesn't really make sense (unless you have lots of servers, which is common anyway, in data centres servers are also controlled remotely just as you would with a mainframe).

Also, mainframes are becoming less and less prevalent, even large scale number crunching systems often use clusters of PCs now. And mainframes don't generally have the same uses as servers, you wouldn't use a mainframe as a web, mail or file server for instance.

Louiseuk25

hmmm, maybe I should accept them as a disadvantage rather than try to understand it. I dont think I should be claiming that what they have written in the text is out of date or doesn't make sense

ManAtHome

A mainframe is just a big server (and they do use them as web and file-servers by the way - IBM offer Linux 'virtual servers' under the CMS O/S).

No real difference to a big PC or Unix-type system - faster as they have very expensive bits inside. The big advantages are that they are less likely to be hacked (relatively cheap to buy a Windows or Linux system to practise on) and the operating system doesn't change very often so you don't have to re-test everything and/or make major hardware upgrades (more of a problem with Windows).

There's also a cultural element - mainframes used to be very expensive (now they're just expensive..), so tended to have physical and logical security in place from the start. Client-server systems are more of a mixed bag - some have similar controls in place, some don't. I worked at one place where they eventually tracked down why some systems had slowed dramatically - somebody had "borrowed" half the memory from a production server to build a test server...

ollyshaw

In my opinion the idea of a mainframe is very outdated. If you need high performance compute use a cluster of "servers" and distribute the jobs across these.

As for your homework, use whatever answer is in the book/notes!

Olly

devizes18193

try a Google for 3270

epz_2

the instinctive answer is a couple of decimal places on the price tag.

mainframes are only for the really big boys these days even banks barely use them.

the big advantage they have appart from the ablliity to hot swap cpus/memory etc is they come with a support package including certified and trained up techs and bonded stock available at a moments notice.

servers can replicate a lot of what mainfraimes do with data replication over multiple loacations etc (not some of the really hard core cpu stuff in high end cores though). basicly it comes down to choice and historic legacy, there didnt used to be people smart enough to setup a redundant unix like system using common hardware, even banks run P4 rackmounts and vpns back to the major SAN's.

google proved with their stratigy of consumer level hardware that you really dont need ultra relable hardware as long as the software is smart enough.

i seriously doubt there are many cpu intensive tasks that need a mainfraime these days outside the military, you could probably buy a shed load of playstation3's stick linux on them and as long as you have a decent data security system have a faster cluster for 1% of the cost.

Woby_Tide

epz wrote: »

the instinctive answer is a couple of decimal places on the price tag.

mainframes are only for the really big boys these days even banks barely use them.

not sure where you get that idea from, the top 3 or 4 in the world certainly have a BIG reliance on mainframes and will do for some time, the smaller banks may get away with switching away but the legacy of the past few decades will take a long time t decomission