STATEMENT OF BILL GATES, CHAIRMAN AND CEO MICROSOFT CORPORATION,
Before the Committee on the Judiciary, United States Senate, March 3, 1998
http://www.igc.apc.org/trac/feature/microsoft/monopoly/gates.html 17 Jan
2002
Microsoft is perhaps best known for developing and marketing operating systems, such as its Windows family of products. Here again, however, we face intense competition from many sources. Dozens of operating systems are available for a variety of computers, ranging from new generations of so-called "information appliances" (such as handheld personal computers or "smartphones") to powerful mainframe computers. IBM alone offers a range of operating systems that include PC-DOS and OS/2 (for personal computers), AIX (for mainframes, servers, workstations and personal computers), OS/400 (for minicomputers), and OS/390 and other mainframe operating systems. Other major operating system vendors include Apple (Macintosh), Novell (IntranetWare), Sun Microsystems (Solaris and JavaOS), Hewlett Packard (HP/UX), Digital Equipment (VMS and Digital UNIX), Lucent (Inferno), Santa Cruz Operation (OpenServer and UnixWare). Overall, Microsoft accounts for just 13% of all operating system-level software revenues (a product category that includes operating systems and related software such as utilities).
[Linux was not in Bill Gates' list. Linux was released in 1994, but had not
yet become a system in widespread use. Linux was distributed under the General
Public License (GPL).]
When purchasing application software, make sure it
is compatible with your particular operating system and hardware!
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Starting a computer
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The process of loading the kernel of an operating system into memory
when a computer is starting is called booting the computer. A few
instructions must be loaded immediately into the computer to begin the
process of reading in the operating system. These few instructions
are called the bootstrap loader. |
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On very old mainframe computers, the computer operator literally keyed
the instructions in binary form into the computer via front panel
controls. The computer was then placed into run mode and these
instructions were executed. The IBM 7040 required 19 instructions
(36 bits each) to read the operating system kernel from hard disk into
memory. |
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Later computers permitted the initial instructions to be read from
paper tape, mylar tape, or aluminum tape. The latter was in a
loop, and was referred to as a bootstrap. The CDC 8090 did
this. |
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On microcomputers today, the initial set of instructions reside in
ROM. If the ROM is located in addressable memory, the contents do
not need to be recopied into memory before being used. This
initial benefit may become a hindrance if that address space is desired
for other code. |
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Starting a PC
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Cold
Boot: Starts the operating system when turning the computer
on.
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Turning the computer off and back on should be the method of
last resort for regaining control of the computer. |
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Warm
Boot: Starts the operating system without requiring the
computer to be turned off and back on.
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On Windows 95 and later: Start | Shutdown | Restart |
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On most PCs: CTRL-ALT-DEL works if the computer is
unresponsive to mouse or other keyboard commands. |
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Some computers have a reset button will restart the computer
without turning the computer off first. |
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Some computers with a reset button starts the boot process at
an earlier stage than done with twice pressing CTRL-ALT-DEL. |
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Sequence |
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Turn on power |
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CPU reset, fetch first BIOS
(Basic Input/Output System) instruction from ROM. |
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Power-On Self Test (POST) from BIOS.
Checks:
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System
buses |
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System
clock |
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Adapter
cards |
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How
much working RAM is installed. |
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Mouse |
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Keyboard |
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Secondary
storage devices (disk drives, etc). |
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Compare POST results with configuration previously stored.
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Amount
of memory |
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Type
of disk drives: # heads, cylinders, sectors per track |
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Keyboard |
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Monitor |
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Current
date and time |
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Other
devices |
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On
most PCs, this is stored in a low power memory chip implemented with
CMOS technology, and hence is often called "the" CMOS chip.
Another name for it is the "BIOS chip", which is more
accurate. (CMOS
technology is used for many other applications too.) |
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BIOS fetches Operating System boot program from the boot
drive: A, CD or DVD, or C |
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Load boot program into memory and execute. |
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Boot program loads OS kernel into RAM. |
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OS loads configuration tables and drivers. |
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OS loads remainder of memory-resident portion. |
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Location of operating system code
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Kernel: The portion of an operating system required for routine tasks
for continuity of operation. The kernel excludes software for
tasks that are performed occasionally. |
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Memory-resident portion: The portion of the operating system kernel
that is retained in memory to minimize the burden for accessing the
secondary storage for operating system code. In a virtual memory
operating system, the memory-resident portion of the kernel is protected
from being swapped to disk. On small memory machines, it is common
for portions of the kernel to be swappable. |
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Windows Registry
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Hardware-specific information for use by hardware detection and Plug
and Play system components. |
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Contains initialization and status information for many application
programs. |
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Can have multiple configurations for the same computer. (Home, travel;
different users) |
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Operating
System Features
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These factors are
major influences on the
sophistication of an operating system:
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Number of users permitted |
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Number of tasks permitted |
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Number of CPUs |
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Single-user, single-tasking |
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Multitasking
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Allows multiple simultaneous tasks in an active state. |
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Foreground, background
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Foreground:
Tasks running interactively with user |
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Background:
Tasks running without user interaction |
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Multi-user, time sharing |
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Preemptive
multitasking: Operating system proactively schedules and
allocates processes to resources according to preset time
slices. |
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Multiprocessing
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Allows simultaneous use of more than one processor.
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Processor assignment and management. |
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Processor coordination: access to common resources, message
passing. |
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Categories:
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Stand-alone: Does not require connection to a network to perform
useful tasks. |
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Network: Two categories.
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Permits (but does not require) connection to a network.
Allows file and resource sharing when a network is
working. Computers with groupware can usually work in
stand-alone mode when the network is down. Murphy's Law:
Networks seem to fail at the worst possible time, and also early
on weekends and holidays. This is when workaholics try to
catch up, and when productive deep thought can take place
without distraction. Essential software should be loaded
on individual computers. |
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Requires connection to a network in order to perform useful
tasks. Network PCs do not have storage or printing
capability. The operating system must use network
resources to perform these tasks. This setup is useful in
a corporate or military setting when it is necessary to control
and account for access to software and data for security
purposes.
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Distributed Computing: Performing processing tasks on a
collection of CPUs, possibly separated by great distances.
There are two varieties. Both varieties require message
passing and semaphores.
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One variety is to split a task into independent
tasks to be accomplished by separate CPUs. Results are
combined in a final step. |
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Another variety partitions a problem into coordinated
tasks which are then accomplished by separate CPUs. The
second variety requires close coordination during task
execution. Personal computers have now been networked to
perform tasks that previously required a supercomputer. |
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Some applications lend themselves well to being
partitioned for execution on a distributed computing
system (multiple CPUs) or network. http://www.psc.edu/htbin/software_by_category.pl/hetero_software |
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Embedded: The operating system resides in ROM rather than on a
disk. This design option is reasonable for small portable or special
purpose computers intended to operate without secondary storage
devices. |
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Fault-tolerant computer:
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redundancy at logic level, or component assembly level. |
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Trap on failure, perform diagnostics, perform or recommend corrective
action. |
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Logic switching is the deselection of bad circuits and selection
of replacement circuits to keep a logic unit working. Building
in the capability to do this is expensive and is not common among
retail consumer electronics. |
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Functions
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Overview
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F
= File Manager |
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D
= Device Manager |
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U
= User Command Interface |
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M
= Memory Manager |
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P
= Process Manager |
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User Command Interface
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Command Line Interface:
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typed input. Many commands, with many
options. DOS: dir , cd.. , cd windows |
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requires use of recall memory |
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requires training and use of
reference material |
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UNIX, DOS are common examples |
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Menu
User Interface
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Common
on mid 1980s computers, and late 1980s laptops. |
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Graphical User Interface (GUI):
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pointing device input. |
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requires use of recognition memory. |
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minimizes training needed for routine productive use. |
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Microsoft Windows, MacIntosh OS,
IBM OS/2, X-Windows |
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Process
Manager
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Schedules use of the processor.
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Keep separate the concept of number of users, number of
processors (CPUs), and number of tasks (processes). |
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| Operating System Types |
Single process
operating system |
Multiprocessing
operating system |
Single task
operating system |
Single user |
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Multitasking
operating system |
Single user
Multiuser (time share) |
Single user (supercomputer)
Multiuser |
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A user is merely a command stream with the ability to initiate an
interrupt. It can be a human sitting at an input device, or it
can be a batch command or script file. |
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A multiple user system must at least be a multitasking system,
since monitoring each command stream is itself a task. |
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A multiplayer game can be a single task running on a single
process operating system. Fir this example, the
"user" is the command stream that invoked the
program. The players are merely providing data inputs to the
game. Responding to player input is done under application
program control. The application program is the single task. |
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A multiplayer game can be implemented to spawn tasks, and thus
need a multitasking operating system. It can also be
implemented to take advantage of multiple processors. |
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A computer with a coprocessor (multiprocessor hardware) can be
used with a single task / single process operating system by
suspending activity of the master CPU and assigning the task to the
coprocessor until the coprocessor is finished. |
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For a coprocessor to perform a task in parallel with a master CPU,
the operating system must be able to spawn a second task and assign
it to the coprocessor, and handle termination of the coprocessor
task when it is finished. It is possible to have an operating
system to handle coprocessors (such as a floating point processor)
as a special case without being designed to handle general
independent processes (tasks). |
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Performance monitor |
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Memory
Manager
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Allocates, schedules, and manages use of primary storage. |
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Buffer |
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Virtual Memory
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Operating system logical address space is larger than primary
storage physical address space. Logical and physical
address spaces are partitioned into pages. Pages of
logical address space that are not needed immediately are placed
onto secondary storage. Windows calls this the swap file. |
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Paging, thrashing |
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Adding more memory does not always cure thrashing.
Sometimes, you need to kill a task
that is memory hungry. Sometimes, this means
uninstalling software that does monitoring functions, such as
parts of Norton System Works. |
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Belady's Anomaly |
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Device
Manager
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Allocates, schedules, and manages use of secondary storage
hardware and other devices. |
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Device driver
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Exchanges
command, status, and data between a device and the
operating system. |
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Plug and Play |
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Interrupt Request (IRQ)
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Error recovery |
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External device interrupt request |
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Virtual Device
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File
Manager
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Manages the file system, and the exchange of data with secondary
storage system. |
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Security and access control. |
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Windows
9x, Windows NT and XP, and Unix file systems are very different and not
compatible.
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Windows is very inefficient in use of large capacity disk
drives.
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28 bits are used in the file allocation table under
FAT32. Cluster size depends on disk capacity. Partitioning
the hard drive into multiple logical drives reduces cluster
size. |
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Logical hard disk cluster size: Windows 98 Resource Kit,
page 401, Table 10.2
| Drive Size |
FAT32 Cluster Size |
| 256 MB - 511 MB |
Not supported. |
| 512 MB - 8 GB |
4 KB |
| 8 - 16 GB |
8 KB |
| 16 GB - 32 GB |
16 KB |
| > 32 GB |
32 KB |
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Files are indexed by a linear linked list structure. |
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Windows writes two file allocation tables on a floppy disk.
Redundancy is for robust use by novices. |
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Unix permits much faster retrieval from large files.
Files are indexed with a tree structure. |
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Administration. (Not part of every operating system.)
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Accounting functions. |
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Access control to system. |
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Enforcement of license restrictions. |
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Popular current operating systems
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DOS, Microsoft Windows 3.x,
Windows 95, Windows 98, Windows 2000, NT, Windows Millennium Edition,
Windows CE, Windows XP |
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Palm OS, Mac OS |
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OS/2 Warp: One of the first PC multi-operating system platforms. |
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UNIX, Linux,
X-Windows |
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Novell NetWare, Banyon Vines, Microsoft Internet Information Server |
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GNOME: Free desktop environment for UNIX
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Utility programs consist of software that perform functions related to the
efficiency of the computer which are initiated upon user command. |
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The dividing line between operating system and utility software is not
always precise. Functions once performed by utility programs
occasionally get built into an operating system.
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In the early 1960s, output from an IBM 7040 intended for the printer
was written to magnetic tape. That tape was then taken to an IBM
1401. A program on the IBM 1401 read the tape and sent the output
to the printer. This program was called a print utility. |
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Screen savers were programs that ran as separate tasks and were not
part of the operating system. Software to invoke the action of
screen savers is part of Windows. Screen savers are still
considered as utility programs, but may later be considered as part of
the user interface portion of an operating system. |
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File maintenance: format, viewer, (de)compression, defragmenter,
uninstaller, backup and restore, anti-virus
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Formatting
is the process of recording the sector boundary codes on a magnetic
disk prior to using the disk for storage of data. |
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Defragmenter:
Reorganizes files to improve read access performance. |
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Personal
Firewalls: Protect computer against unwanted intrusions. |
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Diagnostics: troubleshooting; scandisk; Power On Self Test (POST); performance monitor;
error logging (Dr. Watson)
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Windows
98 System Tools menu:  |
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Maintenance: screen saver (prevents CRT screen burn
on old CRTs), logic switching
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Screen savers are not energy savers. When old monitors were left
on for a long period of time without changing the cursor position,
the character at the current position would become burned into the
phosphor. To solve the problem of physically damaging the tube,
software was written to move the cursor around on the display when
the mouse and keyboard had not been used for some predetermined
period of time. New monitors do not have this problem.
Further, the Energy Star compliant monitors turn off after a preset
time, eliminating the problem completely. Today, screen savers
are primarily entertaining. They serve the useful function of
replacing a display of possibly sensitive information with an
innocuous image. This limits the chance that an unauthorized
person would view sensitive data when the monitor is
unattended. Screen savers can be password protected to prevent
going out of screen saver mode unless a correct password is
entered. This is desirable for people that work with sensitive
corporate or personal data. |
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Power Management:
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Power loss shut down. Belkin UPS has a data cable to a communications
port or USB port over which a signal is sent to the
computer if primary power is lost. A timer is started when a
signal is received. If primary power is not restored before a
predetermined time has lapsed, then power management software
commences an orderly shutdown of the computer. This includes
saving a snapshot of memory or by saving and closing all open files. |
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Standby mode. If a computer is designed to have a standby mode,
the computer will enter the standby mode after a predetermined time
lapse since the last movement of the mouse or key press on the
keyboard. Standby mode may include stopping disk drives. |
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Performance
Monitoring |
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Examples: Norton Utilities |