DAT2330 - Harold Smith Class - Wed Jan 19, 2000 - sorry I'm late - couldn't get the projector from another student - we need installed projectors in classrooms - delete your own messages; clean up after yourself - we may tie marks to leaving junk behind in news groups - peer eval form is posted - tell us why a person didn't get the full team mark - I will modify the percentages if necessary (rare) - hand in forms at same time as project - MVS homework is posted - don't try it yet! Wait for the lecture. It will make sense then. - reiterate web page address and contact information - Tip of the Day (none received yet) - Linux Country - Hints for Success (from students!) - Read the objective, tutorial, text before the class - I've been a student many times; if you don't like learning, this is the wrong profession for you! You must enjoy learning. - Attend class in MVS section of the course - Unix attendance is optional - self study - but watch the web page and news groups - do the homework; practice it yourself or you won't be able to do it - learn how to learn (fishing) - web, discusison group, etc. - email synopsis of news - limit your head banging to 30 minutes - don't waste vast amounts of time (set your timer) - email or post a question asking for help - wait? we review all homework in class - provide accurate info if you need help - screen shots, exact messages, etc. - don't believe rumours - post questions and wait for official reply - make backups - two, in fact - if you don't want to listen, keep a low profile (no talking) - evaluation, earning credit - must pass theory and must pass assignments - can our graduates manage their time (doing assignments) - I will post the reversed course outline - Major O/S - critical to choose O/S correctly, since applications may not move - may need to train people on new software - installation time to install new software - can I find replacements for all my software that runs on new O/S? - what about my own software (not off-the-shelf) - may take years to convert - rewrite custom applications - think carefully about future of organization - DOS/Win3.1 (128K, 256K machines of the day became 640K) - Win95 - August 24, 1995; unstable due to old DOS 16-bit code - O/S should protect itself from bad applications! - Win98 (an upgrade) - Win2K - Professional and Server (based on NT, not 95/98) - "Millenium" follow-on to Win98, based on 98 - MS hopes everyone goes from 98 to W2K/Pro; Millenium is to hedge bets - W2K: better tuning, more tools, more knobs; training needed? - better technical depth to help topics (more help) - WinNT: (NotThere, NotTelling); NT5 has become W2K/Server - good for inexperienced LAN administrators - Unix (Ultrix, AIX, Solaris, HP-UX, Linuxes) - MVS - OS/390 (IBM - popular, expanding) - Open VMS (VAX/VMS) (losing share, dying off) [not same as MVS] - OS/2 - IBM attempt to create a windowing O/S to compete with Win3.1 - great O/S; deserves better market share; stable; secure - IBM blew the marketing - likely on the way out? - MacOS - only on Apple Hardware; came first; much more stable - better design, more efficient; MS stole ideas Major O/S Analyses (some review) DOS/Windows - DOS(81) - Win3.1(90) - Win95 - Win98 - W2K/Pro - Strengths - massive amounts of applications - MS gave away SDK's to people to develop programs - large installed base - GUI good for beginners - multi-tasking (under Windows) - Weaknesses - single-user (can't share with another user) - serious RASSIM weaknesses (at least up to W2K) - GUI is an impediment to experienced users (e.g. changing swap file size to prevent it from eating whole drive; full swap file means you can't save data and you can't quit programs to free up memory! No way to create a shortcut to this dialog box.) Experts want direct access to system services. - WinNT/W2K(server) - designed for 32 bit machines, UNIX-like internals, 12MB for the O/S - 10 times larger than UNIX kernel - Intended for high-end workstations and servers Strengths - 32 bit performance, 3D graphics - Networking (NT/W2K Server) - no experience required to operate - secure Internet access out of the box with inexperienced sysadmin - Win95 GUI (in NT4.0 and later) - you can learn NT: Win95 GUI with Unix-like internals Weaknesses - RASSIM if compared with experienced sysadmin on UNIX/MVS - GUI still a barrier to experienced users - UNIX - architecture designed for program development, not desktops - not designed by a marketing department; two programmers - multi-programming (to share hardware) - designed with a small kernel, most things external to that - can change shells that interact with kernel Strengths - open architecture - started out freely shared - started out open source (now Linux only) - many vendors have a version - humour is in the O/S; strange things you don't see in MS - Unix taught to a generation of university students (free source) - spread and implemented on many types of hardware - runs on just about anything you can program - commercialization of Unix source meant source became secret - Linus Torvalds wrote an open-source Unix that cannot be made secret again - will show you the copy-left document that mandates open source - therefore, I can change hardware and keep Unix for my applications - efficiency and elegance (showing off programming skill) - e.g. putting command in if statement instead of testing $? - better use of hardware; better performance - elegance is expensive if you have to pay for it - much of Unix programming is done for the love of it - File system - performance, security - Linux lets you mount other O/S (for the love of it) - MS does not mount anything else (for the cash) - Powerful Command line interface - but the command names are very terse and not memorable - not easy to learn; but, easy to use - are GUI's better? the modern way? - cmd line is easier to use - e.g. find all files containing a string in MS vs. Unix - MS gives you file names, not the text containing the string - Unix gets you the lines - scripting possible - GUI available to ease transition for new users Weaknesses - Open architecture - but each vendor modified things slightly - too many flavours of Unix; but, only one version of Windows - hard to standardize an O/S whose philosophy is independence! - many Unix GUI's available too! - cryptic command interface - RASSIM (with respect to MVS) - MVS - Multiple Virtual Storages - very large, IBM only, mainframes - VIO - virtual I/O - can pull entire database into memory, kicking out everyone! - JES - job entry subsystem - manage MVS jobs by priority, change parameters, etc. - e.g. you print to Windows and you can't change ordering or copies - reprint a single page from the spool queue - don't want to reprint paycheques! - can't restart some applications that run for hours - need an O/S that has good control of output Strengths - batch job scheduling and control - MVS lets you schedule programs based on *ending* time - deadline priority scheduling - how much memory can be assigned to an application? - big: 16TB in each memory address space! - windows limits programs to 4GB, but O/S takes 2GB, leaving 2GB - still 2GB in Win2000! - hundreds/thousands of address spaces! - best security in the industry - RACF Resource Access Control Facility - best commercial security - available: 99.9999% - minutes per year - system management - central control of systems all across the country Weaknesses - built as batch; not originally interactive; interactivity added later - non-GUI - complex (?) JCL Job Control Language - designed in 1960's; not user-friendly - could you control the same things using anything simpler? - need more info about how things run to implement deadline scheduling - necessary complexity to support features The OS of the Future - picking an O/S is a "bet your company" decision - don't pick one that is going to go away - must handle growth - predict what the O/S will be (you do this in your research project) - Harold Says: - Mainframes - predicted disappearing mainframes (eat your editorial) - size of investment in "legacy" applications - need RASSIM in mission-critical applications - MVS or Unix will run them - prediction: OS/390 (which can now run Unix inside!) - Servers - contenders: Netware(Novell), WinNT, OS/390, OS/2, Unix - Netware has better directory services - Unix (standards? POSIX? Linux?) - good performance; but, complex to administer - too many versions? - prediction: WinNT still easier to install and run on LAN - prediction: UNIX will run on high-performance hardware - Desktop - Win95/98 today; W2K will take over - Unix is not friendly enough; too many GUI - MacOS, OS/2 just haven't made it - prediction: Network Computer / Thin Client - PC will disappear completely - too much intelligence on desktop - centralize the computing; control the software environment - no local data, no way to install software on your own - no floppy, no CDROM; no viruses - no need for everyone to become a system administrator - WinCE, W2K terminal servers, JavaOS, TalOS, Rhapsody, Linux?