Comment from 2001, probably referring to links in the article
Most of the stubbed machines are minis.
Dirani Law Office Video
POV
This seems like so much marketing material from IBM rather than a reflection of the current status of mainframes. The article needs to be heavily edited for balanced point-of-view, substantiated claims, references with a formal, neutral tone.--Preceding unsigned comment added by 67.180.83.26 (talk o contribs) 23:22, 19 October 2006
Agreed, this reads like an advertisement for IBM. (Drn8 (talk) 17:24, 22 August 2011 (UTC))
Other Manufacturers
ICL should be included in the list of mainframe manufacturers and their 2900 series in the list of ranges. Wilmot1 02:55, 1 March 2007 (UTC)
PDPs
Some PDP's were mainframes.
Year 18-bitters 12-bitters 16-bitters 36-bitters 1960 PDP-1 ------------------------------------------------------------ 1961 | \ 1962 PDP-4 <--- LINC -------- \ 1963 | PDP-5 \ \ | 1964 PDP-7 | \ \ PDP-6 1965 | PDP-8 --\ | \ | 1966 | PDP-8/S LINC-8 | | 1967 | | | | PDP-10 KA10 1968 PDP-9 PDP-8/I,L | | | 1969 | | PDP-12 | | 1970 PDP-15 | PDP-14 PDP-11(/20) | 1971 | PDP-8/E / | \ | 1972 PDP-15/76 PDP-8/M PDP-11/05 | PDP-11/45 -- PDP-10 KI10 1973 | / | PDP-11/40 | \ | 1974 | / | | | \ | 1975 PDP-8/A PDP-11/03 PDP-11/04 | | PDP-11/70 PDP-10 KL10 1976 | PDP-11/34 | PDP-11/55 | | 1977 VT78 | PDP-11/60 | | 1978 PDP-11/34C VAX-11/780 PDP-10 KS10
In a nutshell all the 36-bitters were mainframes and the rest weren't.
DEC pulled out of the mainframe business before completing the PDP-10 KC10 and jilted their whole mainframe customer base (including CompuServe and MCI/Tymenet) which marks the beginning of the end for DEC since many of those customers moved to UNIX not VMS where DEC couldn't pull the rug out from under them again. --Preceding unsigned comment added by 66.92.164.43 (talk o contribs) 13:06, 21 December 2002
The PDP-10 is described as a mainframe on its page. The IBM-heavy tone of the article is misleading. Trashbird1240 (talk) 17:17, 13 February 2008 (UTC)
Redundancy
Removed this:
I know this is in the Jargon File, but on reflection a better and more specific source would be nice. --Robert Merkel 05:11, 17 Feb 2004 (UTC)
ENIAC
I removed the following sentence: "For example, ENIAC remained in continuous operation from 1947 to 1955." It makes no sense since Eniac had problem with reability due to the high number of vacuum tubes. There ar no mentioning of this in the ENIAC article. I even doubt that ENIAC could be defined ass a mainframe even if it definitely had the size so did it not have the other characteristics of a mainframe. 82.209.130.109 (talk) 20:53, 26 February 2008 (UTC)
Dumb terminals
mainframes used non-"dumb" terminals, with some editing and form functionality in the terminal itself. in "dumb terminals" each keypress was transmitted to the host, which updated the display accordingly. the "dumb terminal" was coined in contrast to the terminals used before with mainframes that had more smarts. --Preceding unsigned comment added by 213.139.167.121 (talk o contribs) 20:01, 5 May 2004
No he/she isn't "absolutely right". Just because "each keypress" is not "transmitted to the host" (called echoplex) doesn't mean that a terminal is not dumb. It is simply that 3270 terminals were block oriented rather than character oriented; the original 3270 terminals such as 3277 and later the 3278s had no "intelligence in the head" and so were dumb. Not all 3270 terminals are dumb however: a 3277 is dumb (ANR protocol) as is a 3278 (CUT protocol) but a 3270PC/GX is far from dumb (DFT Protocol). Terry. Ex-IBM 3270 specialist. -- Preceding unsigned comment added by 86.134.45.70 (talk) 17:24, 24 August 2011 (UTC)
Supercomputers
comparison with supercomputers: basic idea: supercomputers are for compute tasks, mainframes are for reliability and io problems. actually the difference is pretty hard-and-fast one in my opinion. if you look at products marketed by suprecomputer companies and mainframe companies, you see at least the following differences: supercomputers are geared towards doing computations instead of organising data and shuffling around io. mainframes are engineered for reliability, availability and serviceablity. mainframes typically have relatively feeble cpu power compared to their contemporary high performance computing platforms. mainframes are designed to reliable transaction processing, whereas supercomputers are designed to churn through computative workloads with i/o systems fast enough not to bog down the computation business.
there is a saying: a supercomputer is a machine that converts an i/o bound problem to a compute bound problem.
Isn't it "a supercomputer is a machine that converts an computer bound problem to an i/o bound problem."??? 109.90.35.132 (talk) 16:04, 25 February 2010 (UTC)
sorry i'm not much good with producing wikipedia-quality article text.. --Preceding unsigned comment added by 213.139.167.121 (talk o contribs) 20:17, 5 May 2004
Mainframe language breakdown
Where does the breakdown of programming languages used come from? I know that a lot of mainframe programming was done in Assembler, and much of that code is still out there being maintained. After Assembler, COBOL was popular, and probably is the most popular high-level language out in mainframe-land; but is it 90% of development? I doubt it. Nowadays, there is a lot of development in Java (especially on Websphere [which as far as I can tell is an IBM mainframe version of Apache], but also in CICS). C/C++ has been used for years (I know because I've done some). Then there are all the scripting languages: REXX, EXEC, CLIST, even JCL. --Preceding unsigned comment added by 66.150.41.150 (talk o contribs) 18:28, 12 July 2004
I'd tend to agree with Pluke on this. I've spent 30+ years as an IBM mainframe Systems Programmer, working in many companies in the San Francisco Bay Area (I'm an ex-IBMer and independent consultant), so I think my experiences count. Although there have always been plenty of languages supported under OS/360 and all its successors including today's z/OS, COBOL far and away has been the most-used language for applications programming. Originally, the operating System was written entirely in Assembler for efficiency (Assembler is one-for-one with machine code, whereas COBOL is a high-level language in which each instruction coded generates multiple line of Assembler/machine code). I can't agree that COBOL is even close to Assembler in complexity -- I know both well.
In the 1970's IBM began writing some of the SVS (and later, MVS) code in PL/S (Programming Language/Systems), a language that had a syntax similar to PL/I's. It generated Assembler Code and left the PL/S code in the listing as comments. It was only used within IBM.
Assembler was seldom used as an applications language. The only times I ever saw it were in a few modules that were used to do complex functions that were executed extensively and/or were time-dependent in their execution. Systems programmers always wrote this code, since applications programmers almost never learned Assembler.
No place I've ever worked uses C or C++ on the mainframe, although there was a C compiler generally available starting in the late 1990's on MVS/ESA or OS/390. The only time I ever write in either is for a PC. Since many people have learned C or C++ in college computer science courses (particularly since it's THE language in UNIX and its offshoots), there is undoubtedly more use of those languages on mainframes now than in the past, just not in my experience in large corporations.
EXEC is used only in VM, CLISTs are only used in TSO under MVS and its successors, REXX was first used in VM, then became available for TSO as well. Calling JCL (Job Control Language) a scripting language is really stretching the definition of scripting, but I can understand the thinking. SFFrog (talk) 06:38, 21 July 2009 (UTC)
Speculation on evolution of the word mainframe
This is pure guesswork, but the use of the word to mean "big honkin' MIS computer" has always puzzled me. Here's my speculation. Comments welcome. I always used it to mean "the bay or bays containing the CPU in any floorstanding computer," and was annoyed one day when someone said "that's not what it means; it means a computer that costs more than a million dollars." Here's what I'm guessing took place.
- First, mainframe means "the bay or bays containing the CPU in any floorstanding computer."
- Third-party vendors of plug-compatible peripherals for IBM 360-series computers don't want to mention IBM by name, so start referring to IBM with the circumlocution "the mainframe vendor." Or, people need a neutral or indirect way to say "IBM and/or Amdahl." So the phrase "mainframe vendor" comes into use.
- Extrapolating from this use, "a mainframe vendor" is soon taken to mean "manufacturer of big honkin' MIS computers." Or "IBM and the seven dwarfs."
- One more cognitive step is needed, though, because IBM of course made computers of all sizes. So the next step is "mainframe" comes to mean "the kind of computer most commonly associated with IBM" = "big honkin' MIS computer."
Thoughts? [[User:Dpbsmith|Dpbsmith (talk)]]
--Preceding unsigned comment added by 86.112.41.48 (talk) 20:46, 24 October 2010 (UTC)
I found a website that has some interesting discussion on the etymology of the word mainframe. Not a good RS citation but maybe a good place to add perspective to a search for origins. 159.83.196.19 (talk) 00:11, 16 January 2013 (UTC)
Why did mainframes survive the predicted doom?
They're big and they're very expensive, how come modern day servers with all their claims to be 'autonomic' and with their improved qualities of service, haven't killed the mainframe for good?
Is it just a case of it being too expensive and risky to transfer over to the servers that companies stick with mainframes?
Are there any scenarios that a company would move over to a mainframe solution from a server solution?
Any hard evidence to show the benefits of Mainframes over servers?
How long before they actually die out? --80.40.60.154 18:09, 20 Sep 2004 (UTC)
One cannot ignore simple inertia and platform lock-in. COBOL is not as portable as most literatures makes out. Vendors have, over the years (given the extremely slow rate of change in standards... 1960, 1974, 1985, 2002) have implemented their own extensions. Companies with literally millions of lines of COBOL simply cannot take it off. Additionally, transactionality/unit of work management is important. Without an adequate and performant two-phase commit ability, slowly migrating systems away from the mainframe is difficult. One can think of the mainframe as a nail in the centre of a system, with attempts to migrate away being a rubber band fastened around the nail. Problems often mean that the path of least resistance (if not ultimately the optimal path) is still on the mainframe, being written in COBOL. 7 Jun 2005. --Preceding unsigned comment added by 82.41.212.98 (talk o contribs) 16:42, 9 June 2005
Highly unusual comment been added at the foot of the article, re: Unix having no standards, which is only partially true from the viewpoint of twenty years ago. Mainframe 'standards' are only based on the fact that they are proprietary and hence follow a 'standard' of sorts. A subtle comment indicating that there are 'no known viruses on the mainframe' it seems to me is intended to indicate some sort of design superiority over Unix/PCs/Windows etc. If it were that easy, everyone would be doing it. It seems to me there are various reasons why a virus is unlikely on a mainframe.
- They cost large sums of money (into the millions of dollars) to buy one; hence, hackers typically don't have one in their bedroom
- They operate on closed networks
- There is relatively little documentation on the OS
MetalMickey 20:07, 6 August 2005 (UTC)
A related question is "Why did the conventional wisdom come to believe that mainframes were doomed?" Wikismile 13:53, 12 August 2005 (UTC)
"Undoubtedly debates will continue about the mainframe's value ... The debate began with the 1964 introduction of the IBM System/360 and has continued for over 40 years." I don't recall any debate at all during most of this period. Even during the 1970s, minicomputers represented an expansion of computization rather than a threat to mainframes. Where is the evidence of such debates? --Wikismile 15:20, 26 October 2005 (UTC)
I worked for ICL in the late 1970's and 80's and I do remember debate taking place particularly after the first desktop microcomputers started to appear in the mid-eighties. Part of the reason why mainframes survive is the major costs involved in moving systems. If your system works don't fix it is the attitude. The costs involved in moving systems don't only include the relatively small costs of new hardware and software. They include converting data, retraining staff (particularly management) in the new systems, finding work-arounds for the stuff the old system did but the new system doesn't do. Wilmot1 03:06, 1 March 2007 (UTC)
I've seen no mention of scaling here. With very few exceptions (such as Google's amazing work), mainframes scale better than regular servers or server clusters due to their hardware architecture. Larger amounts of data can easily be stored and accessed more efficiently on a mainframe. Also, the large number of I/O channels makes data availability times shorter.
I believe, however, the main reason mainframes will never die is their reliability and security when compared to any existing alternatives. Their role has changed from what they were in the past. Maybe it's best just to think of mainframes as huge, dependable servers for many applications. SFFrog (talk) 06:53, 21 July 2009 (UTC)
Performance
Finally, I get to ask an encyclopedia a question. What sort of performance do mainframe computers have? CPU speed (GHz)? Number of processors? Number of MIPS? Quantity of memory? I know that there will be a range of values, but it would be good to see either a range of values or particular values for one mainframe type. Thanks. Mjm1964 16:41, 22 Jun 2005 (UTC)
Origin of the word mainframe
I have searched the web for thirty minutes without finding the origin of the word mainframe. Am I the only person out here who knows where the word came from?
In an old electromagnetic telephone central office, each telephone number was associated with a given physical switch. Switches were all wired back to terminal blocks on a big rack. The incoming cables also terminated in terminal blocks on the same rack. Assigning a telephone number to a specific location, i.e., to the copper pair going to that location, was a matter of making a cross connect on this rack. The rack was called the "mainframe".
I don't know exactly how the word got transferred to large computers. I would suppose it came about because at least some of this computer equipment was mounted on standard racks, as was the equipment in a telephone office.
In 1968 in the signal school at Fort Monmouth, one day when we were working on rack-mounted computer components I referred to the rack as a "mainframe". Who out there can claim a computer-related use of the word earlier than 1968?
Joseph Mansfield, 14Aug2005, Jm546
See also 19-inch rack. Jm546 17:12:48, 2005-09-06 (UTC)
It just relates to the primary support structure of the computer, the main framework. The Oxford English Dictionary has a quote from a 1964 Honeywell Data Processing Glossary for main frame referring to the central processor and memory, or that part of the computer exclusive of input output and peripherals. They also have references to "main frame" as early as 1887 in reference to a lathe.--agr (talk) 00:27, 15 December 2009 (UTC)
My recollection of the term "mainframe" relates to the legal battles fought by IBM and third-party peripheral makers. (This would have been late 60's to early 70's.) IBM sought via patents and licensing to prevent any non-IBM hardware from being connected to an IBM system. Ultimately, IBM lost the battle, and the central processing unit, memory, control systems, etc. became the "mainframe," which was IBM's exclusive domain. System users were subsequently free to use third-party peripherals to connect to the mainframe, which was and still is considered the true core of the system. The terminology stuck, and the meaning of "mainframe" morphed to refer to large-scale systems in general. Esjones (talk) 16:20, 27 July 2013 (UTC)
capacity
How many terrabytes? Gazillion bytes?--Jondel 11:44, 21 October 2005 (UTC)
Supercomputer vs Mainframe
Is this correct? (One side effect is that even older software can benefit from adding mainframe CPs.) If so what does CPs mean? Or does it really mean CPUs?--Doc0tis 21:00, 23 November 2005 (UTC)
Whu?
What on earth is "[decreasing] Linux and Java processor prices by about 25%" meant to mean? --Fuzzie (talk) 02:27, 8 March 2006 (UTC)
'IBM mainframes can be fitted with special-purpose processing units that are specific to Java, or to Linux' - read x86 processors to do work to connect IBM's mainframes to the modern world. Funnily enough theres a similar SNA over TCP processor too. --Preceding unsigned comment added by 88.110.45.91 (talk) 16:11, 27 June 2009 (UTC)
Too much POV
Give a careful read to this article, especially the point of view - so many sentences need to be rewritten but I dare not for fear of my own (relative) ignorance of mainframe computers. 71.116.217.242 20:25, 30 March 2006 (UTC)
I have just completed a heavy edit on this article, and I believe it now accurately reflects the facts about mainframes and how they fit into the rest of the computing world. Feel free to carve on it and make it better. RossPatterson 02:27, 14 November 2006 (UTC)
"To give some idea of real world experience, it is typical for a single mainframe CPU to execute the equivalent of 50, 100, or even more distributed processors' worth of business activity, depending on the workloads. Merely counting processors to compare server platforms is extremely perilous." There is a whole discussion on this subject, with the mainframe side pushing the "Mainframes do the job of billions and billions of distributed processors" and Microsoft trying to counter with numbers. I understand a neutral POV would show some specific, concrete, observable, testable situation in which a certain Mainframe CPU, with x processors running with y GHz can provide the same w benchmark as some "distributed" equivalent, such as a Sun or HP blade server with x1 processors, y1 GHz each on the same w benchmark.Ricardo Dirani 14:40, 12 September 2007 (UTC)
http://freespace.virgin.net/roy.longbottom/mips.htm#anchorIBMb
Other Mfg's
I just Wanted to point out that Hitachi Data Systems, HDS was one of the main players in this industry for a very long time, and even toppled IBM for a while. It would be good to mention them. --Preceding unsigned comment added by 24.20.186.59 (talk o contribs) 06:54, 13 July 2006
Reference for IBM mf
Could use a scale-reference for this picture 69.28.40.34 19:52, 2 October 2006 (UTC)
This article was written by IBM's marketing department
I would strongly advise that this article be re-written. It is clearly a product of IBM's marketing efforts. There are numerous self serving statements about IBM being the leader in mainframe technology and an attempt to marginalise the competition. --Preceding unsigned comment added by 70.27.199.213 (talk o contribs) 01:45, 3 October 2006
I was big Univac 1100 mainframe fan -- still am in some ways. As employees, we could not believe how often our product was denigrated because its operating system wasn't exactly like Unix or exactly like what ran IBM's big iron. I suppose there is a human factor that rejects whatever one is unfamiliar with. Still, Univac's 1100 operating system was built to run and did run an efficient mixture of real-time, timesharing, transaction, and batch jobs. Some IBM mainframes required nonsensical software swapouts in the event the customer decided to upgrade his rotating magnetic media. Some IBM software had to run dedicated to a single, physical CPU. (Symmetric multiprocessing? What's that?) The IBM shell was the sole software component with the ability to create and attach a file to a job. So, to compile a Fortran "deck," the shell was required to be instructed to create spill files that were of internal interest exclusively to the Fortran compiler. This could be hidden, somewhat, from the end user. But it smacks of a half-baked idea when what you want is to give the Fortran compiler the ability to create its own spill file as and when it is required. Unix, because of its free distribution among academics, had the patina of being the world's finest operating system, because only the best graduate students ever had an opportunity to enhance it. In comparison to any other operating system, especially commercial ones, Unix was "the best" because of its supposed superiority of design. One design feature of Unix often touted is the ability or requirement to write applications as chains of small, buggy applications linked together via shell script punctuation. Another terrific(?) idea was to make every peripheral device in some way analogous to a teletypewriter. Hence, disk files contain records that are terminated with an ASCII carriage return, or linefeed, or both, which must be catered to by programs reading files that do not subscribe to the concept of communications control characters embedded in data. One man's meat is another man's poison. But Univac managed to avoid most of the nonsense that others cavalierly put into their design and who continue to live with to the present day.--72.75.86.145 (talk) 02:30, 27 December 2007 (UTC)
The article is still written as an IBM advertisement. Just look at the "Market" and "History" contents. It is shameless publicity, dull and plain. And how can you define mainframe as ONLY the computers compatible with the IBM 360 line? That's almost the same as saying the only OS that counts is Microsoft Windows... --190.174.99.233 (talk) 03:53, 14 September 2009 (UTC)
When reading this article, I also had the definite impression that it was all about IBM. alex (talk) 09:24, 28 July 2014 (UTC)
Is this computer, "xyz", a mainframe ?
"Mainframe" might best be defined by example, list the 1st mainframes by the various manufactures. Were the early giants, ENIAC, AN/FSQ-7, ... mainframes? (if weight is the criteria, they're in!). --Preceding unsigned comment added by 69.106.232.37 (talk o contribs) 15:03, 15 October 2006
I think "mainframe" is defined very incorrectly in the main article where the following is stated, "Today in practice, the term usually refers to computers compatible with the IBM System/360 line, first introduced in 1965. (IBM System z9 is IBM's latest incarnation.) Otherwise, systems with similar functionality but not based on the IBM System/360 are referred to as "servers." However, "server" and "mainframe" are not synonymous (see client-server)". In my view, "mainframe" can be used as a term for all general purpose computers prior to the age of PCs and client/server servers. After PCs and servers came along, "mainframe" can be used for all of the other large systems. For sure, "mainframe" is not a System/360 based term and I have held long discussions about ICL and RCA mainframes over the years. {Bruce Palmer -- 8/29/07} --Preceding unsigned comment added by 75.68.166.182 (talk) 15:27, August 29, 2007 (UTC)
Size of the market
I remember reading/hearing that there are 30,000 remaining mainframe sites; IBM recently revealed statistics for 10,000 members of that market. Comments, anyone? --Ancheta Wis 09:31, 1 August 2007 (UTC)
- ^ http://www.cisco.com/warp/public/146/pressroom/1997/oct97/1969.html
MIPS
MIPS is a VAX (minicomputer) term. I have seen it applied to the VAX 11/780, which had several racks of circuit boards, several disks, and attendant terminals and drives. One MIPS meant one 11/780's standard memory, disk capacity and I/O. These are all mini-computer terms, and IBM mainframes had a different terminology and mindset. It might be useful to have a dictionary of the mainframe terms in the encyclopedia. What better place than this article? --Ancheta Wis 09:00, 2 August 2007 (UTC)
I remember reading the 68040 CPU as used in the Mac Quadra was capable of 22 MIPS. This article says the IBM System z9 runs at 26 MIPS. Are the two really equivalent in performance? --Preceding unsigned comment added by 69.125.110.223 (talk) 19:13, 19 December 2007 (UTC)
MVC FOO(256),BAR
MVC FOO(1),BAR MVC FOO+1(1),BAR+1 ... ... MVC FOO+255(1),BAR+255
Linux references
I'm not trying to arbitrarily nuke linux references from the article, it's not like it's not news that IBM supports it on their big iron. I deleted the references because that entire section looked like it was written just to put in OMG IT RUNS LINUX!!! Even the title makes no sense whatsoever. And the fact that IBM promotes Linux on the mainframe is not reason enough to add all that, on the contrary, it looks even more like a press release from them. WP is not a vehicle for commercials about technology.
I suggest adding a separate section, correctly attributed and sourced, about Linux on IBM mainframes (and only in IBM ones, since no other manufacturers support it). And something a bit more neutral than "IBM sells lots of mainframes. They run Linux. Some even run z/OS" would be indicated. §FreeRangeFrog 07:54, 18 October 2008 (UTC)
Statistics
I'm a little confused about the paragraph in the statistics section which says that people think mainframes are expensive, but the reality is different. First, $50,000 still seems expensive. Secondly, I'm not sure where the judgement that it isn't expensive came from; the only thing the reference cited seems to backup is that the OS costs about $1,500. Rnb (talk) 15:25, 2 July 2009 (UTC)
What is it exactly?
This article meanders on through endless "some say, while others say" and "a mainframe does this, sometimes, but not always, and are different from servers, although not necessarily". After reading through it I don't have any idea what a mainframe actually is due to all the weasel words and hedging. - Keith D. Tyler ¶ 21:30, 2 January 2010 (UTC)
Amdahl
I'm not really sure why I started reading this article, but I was surprised that there's no mention of Amdahl. Modal Jig (talk) 19:31, 15 March 2010 (UTC)
90% number
Is there an in-depth source for the claim that IBM has over 90% mainframe market share? All we have right now is an anti-IBM site quoting someone claiming that anti-trust action needs to be taken against IBM. 90% seems very high to me, given that Bull, Hitachi, Fujitsu, NEC, and Unisys all have strong mainframe businesses. Perhaps it refers to 90% of the US mainframe market, or 90% of /390-compatible mainframe sales? Kiralexis (talk) 00:50, 5 July 2011 (UTC)
What happened to midicomputers?
The article divides computers into "minicomputers" and "mainframes", but the industry in the 1960's and 1970's recognized three categories: minicomputers, midicomputers and mainframes. The criteria were somewhat vague, but revolved around memory capacity, price, weight and word size. In particular, the DEC PDP-7 with its 18-bit word, on which UNIX was first developed, was sometimes considered to be a midicomputer. Shmuel (Seymour J.) Metz Username:Chatul (talk) 18:00, 3 August 2011 (UTC)
Deleted POV and weasel word templates
I deleted the very old POV and weasel word templates. I agree that the article could be improved by editing it to a more neutral point of view and use of more concrete lanugage, and also by adding (and following) WP: reliable sources. However, the templates were 2 and 2½ years old, respectively. That is more than ample time for editing. Feel free to improve the article by editing it. However, hanging templates and complaining on the Talk page do not improve the article.--Finell 19:43, 14 January 2012 (UTC)
Characteristics of early mainframes
The description of mainframes in the 1960's being mostly batch is seriously overstated. While batch was common, remote terminals were used interactively even in the 1950's, and the 1960's was the period when online applications emerged into the commercial marketplace.
Shmuel (Seymour J.) Metz Username:Chatul (talk) 20:39, 8 July 2012 (UTC)
Teletypes in the 1960's?
While use of a Teletype® was common in minicomputers, and while the later RCA Spectra 70 used a Teletype®, that was not a common device for mainframe consoles. Several machines used versions of an IBM Selectric Typewriter, but I'm not aware of any mainframe other than the Spectra 70 that used a Teletype®. Shmuel (Seymour J.) Metz Username:Chatul (talk) 20:53, 8 July 2012 (UTC)
MSU
An MSU is a unit of CPU, I/O and storage resource use, not a rate. Further, IBM adjusts the nominal MSU capacities of various models for marketing purposes, so the number of MSUs consumed by the same job will differ depending on which model it runs on and thus MSU's/s does not allow comparing speeds between processors. Shmuel (Seymour J.) Metz Username:Chatul (talk) 19:13, 2 July 2013 (UTC)
Recent edit
Interactive facilities were entering the mainstream in the early 1960's. They started becoming ubiquitous in the mid 1960's.
I/O channels were introduced in the 1950's and were ubiquitous in the early 1960's. It was only entry level machines that did not have them. Channels typically were not computers but comparable to DMA. In the IBM System/360, the smaller models used cycle stealing on the CPU and the larger models used hardwired outboard channels. The peripheral processors on the CDC 6600 were not I/O channels, and every PP had access to every channel. Shmuel (Seymour J.) Metz Username:Chatul (talk) 17:25, 5 July 2013 (UTC)
The following sentence does not make much sense:
"In addition, mainframes are more secure than other computer types: the NIST vulnerabilities database, US-CERT, rates traditional mainframes such as IBM zSeries, Unisys Dorado and Unisys Libra as among the most secure with vulnerabilities in the low single digits as compared with thousands for Windows, Unix, and Linux.[5]"
In particular, the phrase "... as compared with thousands for Window, Unix and Linux." This is comparing mainframes (hardware) with operating systems (software). The IBM zSeries run (or can run) Linux. -- Preceding unsigned comment added by 75.147.4.177 (talk) 15:45, 13 November 2013 (UTC)
Proposed merge with Death of the mainframe
Collection of quotes regarding mainframes. Could also be transwikied to Wikiquote. QVVERTYVS (hm?) 17:25, 25 December 2013 (UTC)
Reference 7
Reference 7 is a dead link. 161.31.231.168 (talk) 00:39, 5 September 2014 (UTC)
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