[HN Gopher] How to tell a mainframe from a minicomputer from a m...
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How to tell a mainframe from a minicomputer from a micro
Author : todsacerdoti
Score : 54 points
Date : 2022-10-07 10:03 UTC (1 days ago)
(HTM) web link (liam-on-linux.dreamwidth.org)
(TXT) w3m dump (liam-on-linux.dreamwidth.org)
| otabdeveloper4 wrote:
| > Separate processors in storage, in terminals, in networking
| controllers, in printers, in everything. Typically the machine
| cannot actually drive any output or input directly (e.g. mouse
| movements, or keystrokes, or anything): peripherals do that,
| collect and encode the results, and send them over a network.
|
| Sounds exactly like USB.
| rvense wrote:
| USB? You mean that thing that all the 8051s use to talk to each
| other?
| masswerk wrote:
| I'd make a point that the entire line of experimental computers
| as developed at MIT and later commercialized by DEC, with an
| emphasis on realtime and graphics, doesn't really adhere to this
| pattern. E.g., we may call the PDP-1 the first commercial
| workstation. (Single user, realtime, graphics, used for
| exploratory work, emphasis on I/O capabilities with a large array
| of input and output devices. But the PDP-1 saw also use as a
| small mainframe and was a testbed for time sharing.) In a sense,
| minis began conceptually as downgraded workstations. (Which
| became viable only as memory cycles shrunk, thus allowing for
| smaller word sizes.)
| matja wrote:
| If there is someone phoning you or knocking on your door when you
| turn it off, it's not a microcomputer.
| manv1 wrote:
| mainframe: building sized
|
| minicomputer: room sized
|
| microcomputer: desk sized
| lproven wrote:
| Oh -- thanks!
|
| It is just a repurposed HN reply, which is why I did not post it
| myself.
| rahen wrote:
| Originally a HN reply posted here:
| https://news.ycombinator.com/item?id=32969692
| lproven wrote:
| Exactly -- that's why I didn't post it.
|
| I write for a living so seldom have time to do it for my blog
| as well -- so I take longer comments from here and other
| places, trim them and post 'em on the blog. Keeps it from
| falling silent.
| psim1 wrote:
| I worked at a company in the early 1990s that ran its business on
| an IBM System/36. It was basically a System/360 but one tenth of
| the size and expense! This was the only minicomputer I ever
| encountered, and I was not responsible for it. I was there to
| work on the "micros" (Windows PCs). I remember the System/36
| programmer making comments about PC techs not being "real"
| computer operators or programmers. She was nearing retirement at
| that time, and if she is still alive I imagine she is enjoying a
| comfortable pension.
| 83457 wrote:
| My mom has had a lot to say about reliability of mainframes
| over PC servers. She worked as mainframe programmer at trucking
| company that had a mainframe, and robotic DVD archives loading
| system, for scheduling and dispatch. PC servers were starting
| to be used for other parts of business.
| klelatti wrote:
| My first job in 1984 included 'selling' System/36s - I say
| 'selling' in inverted commas as I don't think we actually sold
| a single machine - the other part was selling PC/XTs which was
| much easier. Also customers weren't that keen.
|
| By 1990 it would have been a desktop S/36 which sat on or under
| your desktop. The first version was the shape of a washing
| machine but about 6x bigger by volume.
|
| It was also incredibly slow. I later came across an insurance
| company that ran its business on a S/36 emulated on a 386. The
| emulation was faster than the original machine.
|
| From memory I don't think the architecture had much in common
| with S/360. Quite simple I think but a lot of the internal
| state of the processor exposed to the programmer. Might do a
| blog post on it at some point!
|
| Edit; Do let me know if a blog / newsletter post would be of
| interest - details in my bio. Thanks!
| baybal2 wrote:
| projektfu wrote:
| Yeah, sort of, but it's more like this:
|
| First, there were computers. There were some that were made to be
| small enough for a group (IBM 1620, for example), and some that
| were large and intended as the central device for a large
| organization (IBM 7090). IBM referred to both as a "data
| processing system". These were delivered as batch-oriented
| systems.
|
| Large computers like the 7090 often had smaller, accessory,
| general-purpose computers that handled things like card
| reading/punch and printing. For example, the PDP-10 had a PDP-11
| as its front-end controller.
|
| In the late 60s the term minicomputer appeared. A little while
| later, it became popular to refer to the large computers as
| "mainframe" computers. This probably was marketing speak to imply
| that, while minicomputers can be good for somethings, you
| wouldn't mini-frame your house, so you had better main-frame your
| company. I like to think about this time, which was also the
| heyday of database innovation, as the time when companies thought
| there would be many integrated applications running on the same
| data base [two words at the time] operated by a large, reliable
| computer and accessed by peripheral terminals. Through the 80s,
| people in companies often referred to "the computer" rather than
| considering multiple computers as the norm.
|
| Microcomputers appeared with the development of the
| microprocessor. Certainly, the Altair 8800 started the wave of
| using a fully integrated microprocessor as the basis for a
| general-purpose computer. They grew out of calculators and,
| tellingly, from the project to develop an intelligent display
| terminal.
|
| Micros often looked like minis in their use - they might be
| operated by terminals and punched tape, saving onto hard disks,
| floppy disks and magnetic tape. In my opinion, the distinction
| was if you used a discrete ALU, like the VAXes or the Xerox Alto,
| you were still using a minicomputer. Many minicomputers used ECL*
| to achieve high speeds that were not reachable by NMOS or CMOS
| logic at the time. Eventually, minicomputers also became
| microcomputers, for example, the MicroVAX. I think that these
| articles get it right that the microcomputers are different
| because they are not considered to be the orchestrator of a
| system of disks, tapes, terminals, printers, etc. They are at
| best part of a network with specialized microcomputers helping
| share resources when needed.
|
| There is trend of data ending up in silos that happens with
| minicomputers and microcomputers. Applications get written for
| their own data, they aren't given direct access to other
| applications' data, and the data itself is geographically
| distributed.
|
| As time has gone on, we now have the datacenter and
| virtualization. Data has been moving out of silos and into large,
| shared databanks. The computing unit is no longer made out of
| hardware, but rather represented by resources that can be
| provided in many virtualized ways.
|
| * Emitter-coupled logic, a high-speed discrete logic often used
| in supercomputers and fast general-purpose computers until CMOS
| caught up with better power and heat characteristics.
| ghaff wrote:
| At the end of the day, a lot of the classifications are at
| least somewhat historical. And somewhat dependent on what
| operating systems they ran as well in addition to morphing in
| various ways over time. (At some level most modern servers are
| micros unless you're going to create a new category for them as
| you wouldn't usually refer to them that way.)
|
| You also have "Big Iron" Unix servers in there somewhere. And
| various specialty scientific computing systems, e.g. all the
| vector supercomputers etc.
| projektfu wrote:
| Yup, the categories are very fluid now. Considering how many
| businesses "run" on some various software packages these
| days, they all have some sort of mainframe, but it's not
| likely to be one computer. I think, only the minicomputer is
| really gone. There just isn't the same sort of way of using
| the computer that there was in that time.
| zerohp wrote:
| > So as someone else commented, a mainframe isn't really a
| computer, it's a whole cluster of closely-coupled computers, many
| with dedicated functionality. Quite possibly all implemented with
| different architectures, instruction sets, programming languages,
| bit widths, everything.
|
| Nearly all computers more powerful than a simple microcontroller
| look like this in 2022.
|
| If you find this fact surprising, you'll probably want to take a
| look at this talk from USENIX ATC '21:
| https://www.youtube.com/watch?v=36myc8wQhLo
| GMoromisato wrote:
| > a mainframe isn't really a computer, it's a whole cluster of
| closely-coupled computers, many with dedicated functionality.
|
| This is a great description. I think we're moving back to the
| mainframe architecture, but the "cluster" now includes all the
| machines in a data center, plus the mobile and PC clients
| connecting to services.
|
| Tangentially: I talk about how programming models have evolved
| from the mainframe to today here:
| https://gridwhale.medium.com/gridwhale-and-a-brief-history-o...
| rhn_mk1 wrote:
| Considering how many programmable computers with dedicated
| functionality a typical laptop contains, I think they are
| already clusters. Except those are typically not possible to
| program by the user, with a few notable exceptions: some older
| WiFi cards, a few Embedded Controllers. Forget about
| reprogramming the hard drive.
| ncmncm wrote:
| So now microcomputers are mainframes, but with all that extra
| hardware virtualized and emulated.
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