Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site watdcsu.UUCP Path: utzoo!watmath!watdcsu!herbie From: herbie@watdcsu.UUCP (Herb Chong, Computing Services) Newsgroups: net.followup Subject: Re: VM/IX on IBM 4341 (some views from the other side) Message-ID: <722@watdcsu.UUCP> Date: Fri, 30-Nov-84 21:10:52 EST Article-I.D.: watdcsu.722 Posted: Fri Nov 30 21:10:52 1984 Date-Received: Sat, 1-Dec-84 19:40:47 EST References: <117@circadia.UUCP> <411@mhuxd.UUCP> <634@pucc-k>, <18087@arizona.UUCP> Organization: U of Waterloo, Ontario Lines: 220 Extracts from VMSHARE, a community of members of Share who are active and voting members of the VM Committee. Names have been deleted where appropriate. ---------------------------------------------------------------- Comment in "Yes, It Runs on Mainframes" by Donald O'Shea, Amdahl Director of UTS products in ComputerWorld Extra, Sept. 26, 1984: "We believe, in fact, that there will be only two important operating systems by 1990 - MVS and Unix." Reply in VMSHARE: "That's like a choice between death by hanging, or death by firing squad." ------------------------------------------------------------- ...folks who have used real DEC UNIX don't like it (maybe the same way we won't like MVS CMS). ------------------------------------------------------------- Yes we actually have UTS. We have been running it since last August, and are very pleased with the work done by Amdahl. UTS is Unix version 7, with improvements such as a 3270 editor. We also run Unix V6 with PWB on a PDP 11/70, Berkeley Unix on a VAX, Bell's System 3 on a couple of Plexus's (Plexi?). Anyway, all our Unix's are more or less incompatible with each other (so much for 'portable' opereating systems). ...Incidentally, many of our UTS users cannot stand DEC Unix. They often think that VT-100s are very strange terminals compared with 3270s. Other comparisons are interesting; about one in three think Unix is much better than CMS, one in three think CMS is much better than Unix, and the rest think that the two systems are almost identical! --------------------------------------------------------------- [Running UTS,] the IBM architecture easily outperforms the competition too; even with VM, a 4341 MG2 is faster than the VAX/780, and response times are much better (mainly 'cos the DEC screens are so slow). --------------------------------------------------------------- There are plenty of things wrong with Unix, but they do not seem inherent in the design. With software suppliers really having to compete with each other, it should be posible to develop it into an excellent operating system. --------------------------------------------------------------- I can see many advantages in UNIX(*) from the point of view of the professional programmer, but I'm not sure it could hack it in the general user environment we're supporting with VM. Has anybody thought about a serious comparison? I think everyone might be interested in the results. -------------------------------------------------------------- A great many of our users who use both CMS and UNIX express fervant preference for UNIX. None of these people are professional pro- grammers. -------------------------------------------------------------- I would be the first to admit that UNIX is far from a perfect system. It does have many advantages over CMS, however, for both the professional programmer as well as the novice user. Here are some of my favorites: 1. The File System. There is no question that UNIX achieves its greatest degree of user-friendliness through its use of a single integrated file system. CMS suffers greatly through two problems in its file system: First, the inability to share data in a natural and convenient manner at a file level, and second in its flat file structure. Have you noticed that once a minidisk swells to more than 300 or so files that it becomes unmanageable? The CMS filename-filetype convention is nice, but when I have 150 SCRIPT files on my disk the utility of the filetype as a structuring aid is called into question. By the use of directories, UNIX enables me to structure the files under my ownership in such a manner that ls (the UNIX equivalent to LISTFILE) never has to display more than a screen's worth of data. Humanly this is much more manageable than having to stare at pages of LISTFILE output (even if it is displayed fullscreen via FILELIST). 2. Modularity. In UNIX, the fundamental programming concept is the tool. How many times have you cursed (albeit silently) under your breath at a CMS command for not supporting a STACK option which would enable you to use the output of one program as the input of another? If you're into CMS command writing, how many times have you cursed at having to re-write that same STACK code in each and every one of your commands? One of the big differences between CMS and UNIX is that CMS assumes that the output of a program is destined to be read (or printed) while UNIX assumes that the consumer of the output of one program is most likely to be another program. This results in a (some would say too) large collection of primitive functions which enable the experience, and even the not-so-experienced UNIX user to accomplish a task by combining programs in novel ways rather than continually writing new programs. 3. Control. How much discussion has there been in recent years concerning "padded cell" environments? UNIX is DESIGNED around the concept! A padded cell can be as open or as closed as its author desires (the UNIX command interpreter, the shell, is an "open" cell) but there is no such thing as a CP mode to trap the unwary or confuse the innocent. -------------------------------------------------------------------- Things that I do like are 1. The 'pipe' system for sending output from one command to the next. Incidentally I do know of an internal IBM program that does this for CMS! 2. The fact that each program runs in its own process so that any program can call any other program (but watch out for problems if both try to process the same file!) 3. The file system. The tree structure certainly makes management of a large number of files much easier, but I miss the file types. File sharing is easy because of this structure, but read/write access is not so easy. We have both UNIX and CMS, CMS is currently far more popular but UNIX has not been around all that long yet. -------------------------------------------------------------------- I think its interesting how level of expertise reflects in our opinion of the virtues/vices of something. One of the primary vices of UNIX IS the weird command language. For example: cat---- type out a file on your terminal rm ---- delete the file grep ... ---- search file for a pattern Admittedly, the commands DO other things (ie. they are more flexible than the simple description I've provided) but, in fact, this is their main use. Also, I shouldn't have used < and > because thats how the shell decides where to get the input and place the output for commands. Another major problem is the coding of option flags; for example, I find syntax like: "xyz somethingorother -x -n -t -pns" v-e-r-y frustrating. HOWEVER, it is the very terseness of the command and the ability to specify options in a shorthand way that seasoned UNIX users love. The biggest complaint about 327x systems most UNIX hacks have is the inability of the editor, because of the hardware, to deal with each character as it is input. This ability is what gives UNIX the power to support a full screen editor in a text manipulation sense. That is, a single keystroke can be used to mark, pick up, move, or otherwise operate on a block of text. It also gives the ability to support truly interactive programs such as games (I've seen ROGUE, SPACE INVADERS, and even PAC-MAN) on UNIX systems. Its impressive that it can be done, and I can't imagine the tedium of even APPROACHING that level of interactivity (?) on a 327x. Its also EXTREMELY expensive to do i/o that way. If you look at what a player or two of one of those games can do to a system (an i/o interrupt per byte, remember) you quickly realize why you don't let management catch you at it on prime shift. Furthermore, I really like Xedit, and I don't think it lacks anything in the power required to do the editing function. Except for word processing applications, byte at a time control seems excessive to me..., certainly unrequired for professional programmers, or even authors using a formatter (nroff and troff, by the way, insert format control words just like script, so I don't know what the fancy editor buys you there either). I agree with the comment on reliability. Things seem to break for odd reasons (my UNIX colleagues will string me up if they read this), and the machine (the one I'm most familiar with at the moment is a VAX 11/780 with 4Meg of memory -- I think this is about a 158-III) doesn't seem to be able to stand up well to a large user community. 25 users or so and things get perceptably slower (although to be fair, performance is consistently good right up to that point). As for the padded cell, yes, the shell is the perfect (ultimate) cell. Its perfection lies in its flexibility. But how much different is that from CMS, really, if you view CMS as a command processor... a shell of its own. If you think of CMS as a shell, by the way, its not hard to extend the analogy that CMS is what TSO should have been, therefore, run CMS in an MVS address space. I agree with [XXXXX] that not enough has been said about that other VM component ... CP. When it comes down to it (despite that fact that CMS managed to turn out pretty well), CMS might have been as bad as TSO, or as good as UNIX without influencing what is undeniably the best feature of VM, the virtual machine architecture itself. In no other system can I have online users running CICS, ROSCOE (in an OS guest), CMS, UNIX (in a UTS guest) and provide decent service to them all. Not only that, but make them as independant of one another as possible, where none can perceptably hurt another. All that, plus provide a non-intrusive test environment for systems programmers. -------------------------------------------------------------------------- I have talked with some people that use UNIX, some really like the file system, in preference to CMS minidisks. Others say they can never find their files in UNIX because of the directory structure that contains the files. -------------------------------------------------------------------- A few points regarding some of the issues raised in the last few appends: First, ANY command language you're not used to is going to seem a bit strange at first. This is due both to the confusion of the new as well as a desire to retain one's old command framework. cat stands for catenate and does more than perform a 'type' function. However, one of the advantages of UNIX is that it is trivial to create whatever synonyms you wish for commands. ...UNIX can be criticized for its often cryptic commands, but you DO get used to them. Command options are admittedly inconsisent, but then again the same can be said for CMS (some commands support a STACK option, others don't, for example). I agree that raw-mode (the ability to field every keystroke from a terminal) is very expensive, but it is very nice to be able to operate in this manner on occasion (how often have you had to explain how to use the RESET key on a 327x to an impatient user?) ---------------------------------------------------------------- Herb Chong... I'm user-friendly -- I don't byte, I nybble.... UUCP: {decvax|utzoo|ihnp4|allegra|clyde}!watmath!watdcsu!herbie CSNET: herbie%watdcsu@waterloo.csnet ARPA: herbie%watdcsu%waterloo.csnet@csnet-relay.arpa NETNORTH, BITNET: herbie@watdcs, herbie@watdcsu POST: Department of Computing Services University of Waterloo Waterloo, ON N2L 3G1 (519)885-1211 x3524 -- Herb Chong... I'm user-friendly -- I don't byte, I nybble.... UUCP: {decvax|utzoo|ihnp4|allegra|clyde}!watmath!watdcsu!herbie CSNET: herbie%watdcsu@waterloo.csnet ARPA: herbie%watdcsu%waterloo.csnet@csnet-relay.arpa NETNORTH, BITNET: herbie@watdcs, herbie@watdcsu POST: Department of Computing Services University of Waterloo Waterloo, ON N2L 3G1 (519)885-1211 x3524