David's Blog

2006-12-06T18:50:00.000-08:00

UNIX Command Summary
There are MANY commands available for you in a UNIX shell account. A list of them follows (in no particular order). Remember, you can always read the manpage on each command for more information.

ls ................. show directory, in alphabetical order
logout ............. logs off system
mkdir .............. make a directory
rmdir .............. remove directory (rm -r to delete folders with files)
rm ................. remove files
cd ................. change current directory
man (command) ...... shows help on a specific command
talk (user) ........ pages user for chat - (user) is a email address
write (user) ....... write a user on the local system (control-c to end)

pico (filename) .... easy to use text editor to edit files
pine ............... easy to use mailer
more (file) ........ views a file, pausing every screenful

sz ................. send a file (to you) using zmodem
rz ................. recieve a file (to the unix system) using zmodem

telnet (host) ...... connect to another Internet site
ftp (host) ......... connects to a FTP site
archie (filename) .. search the Archie database for a file on a FTP site
irc ................ connect to Internet Relay Chat
lynx ............... a textual World Wide Web browser
gopher ............. a Gopher database browser
tin, trn ........... read Usenet newsgroups

passwd ............. change your password
chfn ............... change your "Real Name" as seen on finger
chsh ............... change the shell you log into

grep ............... search for a string in a file
tail ............... show the last few lines of a file
who ................ shows who is logged into the local system
w .................. shows who is logged on and what they're doing
finger (emailaddr).. shows more information about a user
df ................. shows disk space available on the system
du ................. shows how much disk space is being used up by folders
chmod .............. changes permissions on a file
bc ................. a simple calculator

make ............... compiles source code
gcc (file.c) ....... compiles C source into a file named 'a.out'

gzip ............... best compression for UNIX files
zip ................ zip for IBM files
tar ................ combines multiple files into one or vice-versa
lharc, lzh, lha .... un-arc'ers, may not be on your system

dos2unix (file) (new) - strips CR's out of dos text files
unix2dos (file) (new) - adds CR's to unix text files

2006-11-29T03:57:00.000-08:00

Components of Operating Systems

Process Management:

Providing multiple processes allows conceptually concurrent processing, assisting with modularisation of the program.

The OS provides for creation, deletion, suspension, resumption of processes.
Processes often require synchronisation and communication with each other - the OS must provide facilities for this.

As multiple processes wish to share resources, resource allocation is required.

With this come problems of deadlock and starvation which must be treated.

Memory Management:

The aim of memory management is to allow processes to use as much as possible of the memory, whilst giving each as much as it requires.

The operating system is responsible for allocating memory to processes, and keeping track of free memory.

Segmentation and/or paging may be implemented. Segmentation avoids internal fragmentation, paging avoids external fragmentation.

Virtual memory uses secondary memory to emulate main memory.

File Management:

The objective of the file system is to provide a user-friendly interface to a large structured persistent storage area.

The file system usually has a directory structure. A directory is a file which contains information about the location of other files.

The file system provides facilities to manipulate files and directories.

Input/Output Management:

The objective of I/O system management is to provide controlled (non-interfering) convenient access to I/O devices.

Efficiency is improved by buffering, caching and spooling.

Device drivers are low-level software interfaces to devices.

2006-10-08T21:51:00.000-07:00

Im not doin much so im gonna make a post...this goes out to everyone that feels like they're feelin down cuz of all the crud people throw their way...so chin up peeps and tell those ***es to s**k it!

2006-10-04T20:01:00.000-07:00

Updated my blog...yo add me up at friendster people...heres my email add: j_erkz_2004_2005@yahoo.com . Yes it is 2004-2005 cuz im just too lazy to change it...however i have an active ym accnt...add me up here too: j_erkz20062007. rÖk ON!

2006-10-02T16:59:00.000-07:00

Intel's Core architecture now underlies mobile, desktop and server chips, and is a major departure from the Pentium 4's NetBurst design.

It is hard to overstate the importance of the Core micro-architecture to Intel, and thus to the rest of the industry. The product of a major debate within Intel (what Pat Gelsinger, General Manager of the Digital Enterprise Group, called the 'speed freaks versus brainiacs'), it marks the victory of those who felt that extra performance was best achieved not by constantly upping the processor's clock speed, but by going for ever more parallel systems with much finer control of performance versus power consumption.
With the Core 2 Duo and Core 2 Extreme, the Core architecture is being applied to mobile (Merom) and desktop (Conroe) processors, which now join last month's Xeon 5100 (Woodcrest) to put basically the same chip in everything from notebooks to servers. All modern processors work by reading a stream of instructions that tell them where data is in memory and what to do with it. Originally, processors took in one instruction from memory and took as long as it needed to fully execute it before starting on the next. Each clock tick -- of which there are a million a second with a 1MHz processor, a billion with 1GHz -- moved the instruction one stage further through the processor. Some instructions could take four or more ticks.

2006-10-02T16:41:00.000-07:00

Why do I love using Computers?

Computers play a vital role in my life...such as for leisure, I like playing computer games cuz hey its cool... Computers also help me in making assignments, requirements needed in school and the likes. Downloading... I dig downloading stuff off the internet like movies, songs, but not illegally of course (if u get wat i mean ^^,). Right now we live in the modern age... a time in which technology plays a very important role in the development of society... cuz of this many people my age are so caught up in the technology that we have today that it forces us to make ourselves better so that we can be more adaptive to the changing times.

2006-09-12T23:17:00.000-07:00

10 years after the life of one of the greatest Rappers was took...let us take time to commemorate the words of this great person...

2006-09-12T22:59:00.000-07:00

Computer Architecture has shown me that even though programmers deal with programs and the likes, if our knowledge of computer architecture is limited, then we are almost completely useless. If we know nothing about data structures or how and why the structures of data or so complex then we know nothing.

2006-09-11T17:26:00.000-07:00

CS 212 (Computer Architecture)

I have learned lots of things in this subject during the first and second trinals of school year 2006 - 2007. I discovered the ways to pipeline, store, and edit data. Things like this are important in the life of a computer programmer cuz they help to make the understanding of data structures a lot more easier.