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Kernel, Modules, Mbr and Stuff:
NOTE: Review the Nerd, Fdisk & Partition pages for more
info on the Master Boot Record.
Microsoft isn’t saying much, but we will. Over the short term, you can expect
quarterly service
packs for NT 5.0 and Windows 98. By 1999, we expect Microsoft to evangelize its
"Windows 2000"
initiative, which involves developing all consumer and corporate Windows upgrades on the
NT
kernel.
A little Master Boot Record Info:
PARTITION SECTOR/RECORD/TABLE BASICS
FDISK creates all partition records (sectors). The primary purpose of a partition record
is to hold
a partition table. The rules for how FDISK works are unwritten but so far most FDISK
programs
(DOS, OS/2, WinNT, etc) seem to follow the same basic idea. First, all partition table
records
(sectors) have the same format. This includes the partition table record at cylinder 0,
head 0,
sector 1 -- what is known as the Master Boot Record (MBR). The last 66 bytes of a
partition table
record contain a partition table and a 2 byte signature. The first 446 bytes of these
sectors usually
contain a program but only the program in the MBR is ever executed (so extended partition
table
records could contain something other than a program in the first 466 bytes). Second,
extended
partitions are "nested" inside one another and extended partition table records
form a "linked
list".
PARTITION TABLE ENTRY FORMAT.
Each partition table entry is 16 bytes and contains things like the start and end location
of a
partition in CHS, the start in LBA, the size in sectors, the partition "type"
and the "active" flag.
Warning: older versions of FDISK may compute incorrect LBA or size values. And note: When
your computer boots itself, only the CHS fields of the partition table entries are used
(another
reason LBA doesn't solve the >528MB problem). The CHS fields in the partition tables
are in
L-CHS format --- CHS Translation".
There is no central clearing house to assign the codes used in the one byte
"type" field. But
codes are assigned (or used) to define most every type of file system that anyone has ever
implemented on the x86 PC: 12-bit FAT, 16-bit FAT, HPFS, NTFS, etc. Plus, an extended
partition also has a unique type code. Note: I know of no complete list of all the type
codes that
have been used to date. For more information on this subject (see the NERD pages).
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So what's a kernel, (it's a number of things explained in short) but it's basically the
architecture
of Windows or any operating system:
Central System:
The central module of an operating system. It is the part of the operating system that
loads first, and it remains in main memory. Because it stays in memory, it is important
for the kernel to be as small as possible while still providing all the essential services
required by other parts of the operating
system and applications. Typically, the kernel is responsible for memory management,
process and task management, and disk management.
Module, explain it:
In software, a module is a part of a program and programs are composed of one or more
independently developed modules that are not combined until the program is linked. A
single module can contain one or several routines.
In hardware, a module is a self-contained component.
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A Operating System:
Operating systems provide a software platform on top of which other programs, called
application programs, can run. The application programs must be written to run on top of a
particular operating system. Your choice of operating system, therefore, determines to a
great extent the applications you can run. For PCs, the most popular operating systems are
DOS, OS/2, and Windows, but others are available, such as Xenix.
As a user, you normally interact with the operating system through a set of commands. For
example, the DOS operating system contains commands such as COPY and RENAME for copying
files and changing the names of files, respectively. The commands are accepted and
executed by a part of the
operating system called the command processor or command line interpreter.
Graphical user interfaces allow you to enter commands by pointing and clicking at objects
that appear on the screen.
Memory thing:
Refers to physical memory that is internal to the computer. The word main is used to
distinguish it from external mass storage devices such as disk drives. Another term for
main memory is RAM.
The computer can manipulate only data that is in main memory. Therefore, every program you
execute and every file you access must be copied from a storage device into main memory.
The
amount of main memory on a computer is crucial because it determines how many programs can
be executed at one time and how much data can be readily available to a program.
Because computers often have too little main memory to hold all the data they need,
computer
engineers invented a technique called swapping, in which portions of data are copied into
main
memory as they are needed. Swapping occurs when there is no room in memory for needed
data.
When one portion of data is copied into memory, an equal-sized portion is copied (swapped)
out
to make room. Another technique, called virtual memory, enables a computer to access
larger
amounts of data than main memory can hold at one time, but it is a relatively slow
process.
Therefore, the more memory a computer has and the more it can avoid swapping, the faster
it will
be able to execute large programs.
Now, most PCs come with a minimum of 8 megabytes of main memory. This is adequate for
some applications, but you may need more memory to run sophisticated applications,
particularly
those that include graphics. You can
usually increase the amount of memory by inserting extra memory in the form of chips or
memory
expansion boards.
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Applications thing:
A program or group of programs designed for end users. Software can be divided into two
general classes: systems software and applications software.
Systems software consists of low-level programs that interact with the computer at a very
basic level. This includes operating systems, compilers, and utilities for managing
computer resources.
In contrast, applications software (also called end-user programs) includes database
programs, word processors, and spreadsheets. Figuratively speaking, applications software
sits on top of systems software because it is unable to run without the operating system
and system utilities.
Disk & Data:
A machine that reads data from and writes data onto a disk. A disk drive resembles a
stereo turntable in that it rotates the disk very fast. It has one or more heads that read
and write data.
There are different types of disk drives for different types of disks. For example, a hard
disk drive (HDD) reads and writes hard disks, and a floppy drive (FDD) accesses floppy
disks. A magnetic disk drive reads magnetic disks, and an optical drive reads optical
disks.
Disk drives can be either internal (housed within the computer) or external (housed in a
separate box that connects to the computer).
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