================================== Summary Slide for O/S Introduction ================================== -IAN! idallen@idallen.ca (Based on an original by Harold Smith) 1. What is an Operating System? a. 'Software intended to aid in the preparation and execution of application programs' (Harold) -OR- b. 'Manages the Hardware' (Ian) 2. OS Evolution - 1 Users -> Application Program -> *** OS *** -> Hardware 3. OS Components a. Boot Facility (IPL) b. Shell (Command Processor, GUI, JCL) c. Task Management d. Memory Management (Virtual Memory) e. I/O Ctrl System (Data Mgmt, Device Drivers) f. Security System g. Networking Facilities h. Utilities (System Tools, Text Editor etc.) i. HELP facilities 4. OS Terms a. Kernel (nucleus) - that portion of the OS that is running at all times. b. Batch vs Interactive Processing -periodic transaction processing vs as occurring' c. Spooling - printer management d. Batch Files (macros, WSH, shell scripts, "procs") e. Multitasking vs Multiprogramming 5. OS Selection Criteria RASSIM: Reliability, Availability, Serviceability, Scalability, Integrity, Manageability a. Performance (Throughput vs Response Time) b. Availability (Reliability, Serviceability) c. Manageability, Scalability d. AP's/SDK's available (Watch for Vapourware) e. User Friendliness i. Ease of learning vs Ease of use ii. Tailorability f. Security g. Cost (SW, HW, install, support) 6. Major OS's a. Microsoft DOS/Win 3.1 - Win95/98 - WinME b. Microsoft Win/NT - Win2000 - WinXP c. UNIX (DEC Ultrix, IBM AIX, Sun Solaris, HP-UX, Apple MacOS-X) Linux - no one vendor (Mandrake, Red Hat, Debian, SuSE, etc.) d. IBM MVS - OS/390 e. DEC Open VMS (VAX/VMS) f. IBM VM/XA, VSE g. IBM OS/2 h. Apple MacOS (System 7, 8, 9) 7. DOS/Windows a. DOS (81-128K XT) + Win3.1(90)->Win95/98->Win2K->WinME->WinXP->?? Windows 98: Suggested "Improvements" over Win 95 i. improved administration tools ii. support for new hardware iii. more efficient file system iv. automated updates via Web browser v. Win Scripting Host (VBS, JS) vi. integrated IE, Active Desktop interface b. Strengths i. AP's available (Installed base) - more than 100M copies sold so far - more than>80% of PC market, and share growing (PCMag) ii. GUI, Multitasking iii. 9 out of 10 (home) users satisfied c. Weaknesses i. single user ii. Task/memory mgmt problems iii. stability, security iv. GUI! v. Constant O/S upgrading and obsolescence - Integrating and maintaining 32-bit OS's "top concern" - survey of 200 IT mgrs at Fortune 1,000 companies. (Datamation) vi. Active Desktop will mean extensive training vii. Windows Update: one of the most compelling features of Win98 - one of the least suited for corporate use: (PCWeek) 8. WinNT / Windows 2000 a. Arch i. 32 bit, UNIX-like; but: 12MB for OS! ii. Intended for high-end workstations and servers b. Strengths i. 32 bit performance, 3D graphics support ii. Networking (NT server) iii. Secure Inet access iv. Win95 GUI (in NT 4.0) c. Weaknesses i. lack of RASSIM (vs. UNIX, MVS) iii. See Datamation article: aunixserver.txt iv. GUI (weak batch processing tools) 9. UNIX a. Arch - designed for MT program devel't, kernel/shell b. Strengths i. Cross vendor / cross platform support ("Open Arch") ii. Efficient, elegant kernel, MT iii. File System iv. Powerful command line interface c. Weaknesses i. Open Architecture! (incompatible versions) ii. Cryptic cmd interface (X Windows GUI may help a bit) iii. Lack of RASSIM (except on IBM hardware?) 10. UNIX Demand? a. Internet! the slashes go forward, not backward! b. Internet, WWW, TCP/IP, all Unix-based c. >60% of Inet servers are Unix today d. >80% of Inet firewalls are Unix e. 1.5 jobs for every available consultant @ $40-60/hr -SVN f. Linux Interest! - NASA using for new space station - MS mentions Linux as only OS named when explaining competition 11. IBM MVS (Multiple Virtual Storage) a. Arch - Multiple Virtual Storages, VIO, JES b. Strengths - "85% of existing mainframe apps will stay right where they are to take advantage of mainframe security, performance, and reliability" (Gartner Group) - The mainframe is a natural for e-commerce because that's where the data typically resides. (Datamation) - RevCan, Statcan, CSIS, Bank of Can etc. are MVS shops - no signs of extinction - shipments of System/390 growing steadily since 1994 i. batch job scheduling and control ii. big (eg 16TB per address space) iii. security (RACF), availability (99.9999%) iv. system management facilities c. Weaknesses i. interactive facilities added later (non GUI) ii. complexity (necessary?), JCL interface 12. The OS of the Future a. Mainframes i. will be with us for the foreseeable future due to... (a) size of investment ('legacy applications') (b) RASSIM' needs of 'mission critical apps' ii. MVS/UNIX, OS/390 b. Servers i. Netware vs WinXX vs OS/390 vs OS/2 ii. UNIX (std version? POSIX? Linux?) c. Desktop i. Win95/8 vs WinNT/2000 vs UNIX (MacOSX, OS/2?) ii. NC - WinCE? W2KTrmServs? JavaOS? TalOS? Rhapsody? (1) Linux!