SEB070016-TUTORIAL5

TYPE OF DIRECT ACCESS STORAGE DEVICE












Magnetic Disk


DESCTIPTION
A memory device, such as a floppy disk or a hard disk, that is covered with a magnetic coating. Digital information is stored on magnetic disks in the form of microscopically small, magnetized needles, each of which encodes a single bit of information by being polarized in one direction (representing 1) or the other (representing 0).
Magnetic disc is the primary computer storage device. Like tape, it is magnetically recorded and can be re-recorded over and over. Disks are rotating platters with a mechanical arm that moves a read/write head between the outer and inner edges of the platter's surface. It can take as long as one second to find a location on a floppy disk to as little as a couple of milliseconds on a fast hard disk


EXAMPLE
HARD DISK AND FLOPPY DISK


ADVANTAGES
high storage capacity,
reliable gives,
direct access to data.

Optical Disk


DESCRIPTION
Is an electronic data storage medium from which data is read and written to by using a low-powered laser beam. It is flat, circular, plastic or glass disk on which data is stored in the form of light and dark pits. The laser beam reads the pits and the data can be accessed


EXAMPLE
Read-only optical disk,WORM,Rewritable/Magneto-optic disks


ADVANTAGES
An optical disk has much more storage capacity on the order of gigabytes, than a magnetic disk. It can hold up to 6GB of data in comparison to 1.44 MB of a diskette. Optical disks are inexpensive to manufacture. Data stored on optical disks is resistant to power surges or magnetic disturbances, such as head crashes or corruption form stray magnetic fields. Hence, they provide high data stability. Optical disks are less vulnerable to extremes of hot and cold as compared to the magnetic disks. Optical disks have long media life than magnetic disks.















Flash Memory

DESCRIPTION
Flash memory is non-volatile computer memory hat can be electrically erased and reprogrammed. It is a technology that is primarily used in memory cards and USB flash drives for general storage and transfer of data between computers and other digital products. It is a specific type of EEPROM (Electrically Erasable Programmable Read-Only Memory) that is erased and programmed in large blocks; in early flash the entire chip had to be erased at once. Flash memory costs far less than byte-programmable EEPROM and therefore has become the dominant technology wherever a significant amount of non-volatile, solid-state storage is needed.


EXAMPLE
thumb drive, key drive, and mini-USB drive.


ADVANTAGES
The advantages of flash memory as compared with HDDs are substantial. They include smaller size, lighter weight, a far lower power consumption, longer life expectancy and greatly improved shock resistance.
















Magneto-optical Disk

DESCRIPTION
A magneto-optical drive is a kind of optical disc drive capable of writing and rewriting data upon a magneto-optical disc


EXAMPLE
magneto optical drive


ADVANTAGES
A magneto-optical disc comprising a recording layer and a protective coating on a substrate is operated for magneto-optical recording in a magnetic field modulation mode such that the protective coating is in sliding contact with a magnetic head.

SEB070016-TUTORIAL 4

LINUX	WINDOW
how Linux implement virtual memory: The virtual memory feature of Linux makes the operating system behave as if it has a larger memory than the actual memory size. Linux moves blocks of memory called pages in and out of a special memory area, called swap space, in the hard disk. The MMU converts the address specified by the register, also known as the linear address, to the actual physical address for the data to be accessed. This process is termed page conversion and occurs in three stages of mapping: Page table contains the addresses of memory pages. Page middle directory contains the addresses of page tables. Page directory contains the addresses of page middle directories. The three-level architecture resolves the problem of large intermediate entries generated while resolving addresses.	How window perform and implements virtual memory: RAM generally not large enough to hold all of the running programs, so Windows sets up some additional virtual memory as a file on the hard drive. It then swaps portions of the programs between the physical and virtual memories, always having the currently active portion of a program in the physical memory. - Windows sets the default minimum size of virtual memory at 1.5 times that of the RAM, and the maximum size at 3 times the minimum. - Windows then manages the actual size, expanding and contracting it as needed within these limits. Memory manager implements virtual memory provides a core set of services such as memory mapped files, copy-on-write memory, large memory support, and underlying support for the cache manager.
uses demand paging to load executable images of the running program in the memory page size: Linux uses the Least Recently Used (LRU) technique to manage pages in memory. LRU removes the oldest unaccessed page from the main memory in order to create space for the new page. The list of pages is maintained by the kernel. The age of the pages is incremented by the kernel periodically. Whenever a request for a page is made, the LRU algorithm verifies the highest age count in the list and allocates the page accordingly	Doesn’t use demand paging. item that loaded in RAM is the non-paged area and page pool Page size: in Windows XP, when we added more memory to computer, we had to manually go and increase the size of your paging file to correctly match the amount of memory in your computer. Windows Vista does away with this by automatically setting the optimal size for the paging file, even after you add more memory to your computer. For example, if computer with 1GB of memory, paging file would be roughly 1300mb, but if we add another 1GB of memory to computer to make a total of 2GB, now when look at the paging file, it will have automatically increased
page fault handler determines what must be done to resolve this page fault 1) Find where the desired page resides on disk and read it in 2) Determine that the desired page is already in RAM and direct the MMU to point to it Kernel-handle page fault: identify the type of the requested virtual memory access and take the appropriate action to allow or deny application's VM request.	Using page handler 1) It can decide the virtual address is just simply not valid. In this case, Windows will report this error back by indicating an exception has occurred (typically STATUS_ACCESS_VIOLATION) -2) It can decide the virtual address is valid. In this case, Windows will find an available physical page, place the correct data in that page, update the virtual-to-physical page translation mechanism and then tell the hardware to retry the operation. When the hardware retries the operation it will find the page translation and continue operations as if nothing had actually happened.
use signals, such as SIGSEGV , to report these error conditions to programs	uses structured exception handling to report page fault-based invalid accesses as access violation exceptions
Thrashing issue could be reconcile with Resolving the excessive memory paging by temporarily helping one of the active processes quickly build up its working	Thrashing a process is busy swapping pages in and out -Increase the amount of RAM in the system to eliminate the cause of thrashing - Reduce the amount of RAM needed by reconfiguring the applications, removing unneeded system services (like network protocols that aren't being used), or running fewer applications at a time - Try to optimize the paging file's activity

i'm totally EmO 2day..!!!

ELE..TRICK

Orang Melayu dikatakan mengambil perkataan ELEKTRIK daripada perkataan Inggeris yang juga ELECTRIC. Tetapi yang sebenarnya, ELECTRIC itu diambil dari perkataan Melayu campur Inggeris.
Ceritanya… . Pada suatu masa dulu selepas setahun Thomas Edison mencipta lampu, saintis tidak pernah terfikir memberi nama kuasa yang menyebabkan lampu itu hidup. Jadi, entah macam mana semasa lampu mula-mula hendak diperkenalkan di Tanah Melayu, ada seorang Melayu yang bernama Kulup Kalimantang mati-mati tidak percaya pada hasil ciptaan Thomas Edison itu. Semasa demonstrasi diadakan oleh Thomas di Tanah Melayu untuk memperkenalkan lampu itu, Kulup Kalimantang pun berkata dengan kuat.
“Ele..trick aje tu… ele..trick aje… ele trick!”. ( Bermaksud tipu )
Thomas Edison berfikir Kulup berkata begitu kerana mengatakan lampu menyala disebabkan oleh kuasa “ele..trick” . Jadi digunakanlah perkataan “ELE..TRICK” yang dieja ELECTRIC mengikut ejaan orang putih. Sebagai mengingati jasa Kulup Kalimantang menamakan kuasa ELECTRIC itu, maka diciptalah sejenis lampu panjang yang dinamakan lampu kalimantang

i love converse....so many thing!!!!

computer-terminology-bm-vs-biharu-jadinya..

Some computer terms translated to BM,
Don’t you think that computer terminology in Bahasa Malaysia is really weird?
Cakera Keras = Hard Disk
Tetikus = Mouse
Papan Kunci = Keyboard
CD-ROM = Cakera Padat Ingatan Melalui Pembacaan (CP-IMP) - Isn’t that bit too much to ingat? Try pronouncing that without twisting your tongue or pausing to think. IMPs?
Monitor = What’s the term for this? KETUA DARJAH?
Modem = Could it be called “PEMPEND” <– PEModulasi, PENDemodulasi?
Motherboard = “Papan Ibu” probably? Maybe the best motherboards can be awarded the “Papan Ibu Mithali” then?
Sound Card = Kad Bunyi?
Sound Blaster = Peletup Bunyi?
Pipeline Burst Cache = Duite Garisan Paip Meletup?
Local Bus = Bas Tempatan? Sounds good to me.
VESA Local Bus = Bas Tempatan VESA?
Flatbed = Katil leper? OR Katil Rumah Pangsa (Flat)?
WWW = Sarang labah-labah Selebar Dunia (SSD)? Sounds quite convincing to me.
Then what would you call daughterboards? Papan anak perempuan? That sounds a little kinky for me :)) What about SIMMs and DIMMs and such…?
*laf* wonder what would you call ink jets then Pancutan Dakwat???
What about “Plug and Play [tm]“? Hmmm..Plug and play….Cucuk dan Main??? Somehow I think not.

SEB070016-TUTORIAL 3

Operating System is an Interface between User and the Computer.this is very clever software that allows you to speak to the computer and tell it what you want it to do. Before operating systems were around, there was very little you could do with a computer. Any information you needed to enter was long-winded and time-consuming - no such thing as clicking on links or icons.


OS is the most important program that runs a computer;
20 core function of operating system is:

1)enable human interaction with machine and allows us communicate with the computer and tell the computer what we want to it to do,such as searching data,save file,delete the folder,rename the folder and etc.

2)kernel
- provide access to various common core services to allother system and application programs. These services include, but are not limited to: disk access, memory management, task scheduling, and access to other hardware devices.

3)allocating the processes and resources
-allocated each process a certain amount of time to use the processer
-allocated various resources that processe will need such as computer memory stick or disk

4)security
-perform security such as prevent other user from accesing our computer system such as perform password using

5)manage software and hardware such as control the disk drives,scanner and printer

6)recognizing input from the keyboard

7)sending output to display screen

8)manage all process that are running on a computer

9)deal with error and user interaction

10)control the loading and running program

11)control the transfer data to peripheral such as scanner and printer

12)allow the user to save the data or file to a backing store

13)enable timesharing; in whiich many application program seem to be running simultaneously but are actually "taking turn" by coordinating with hardware operation

14)distributed with tools for programs to display and manage a graphical user interface

15)enable virtual memory operation for applications program,which allow flexible use of memory and enforce security

16)maintain the file system on computer

17)load application programs for execution

18)coordinating the activities on computer

19)support the creation,execution and destruction of processes

20)enable the user to search or access the data information from the internet explorer,mozila firefox and etc.

SEB070016-TUTORIAL 2

APPLICATION SOFTWARE
Application software also called end-user program..It Is one that makes the computer cooperate with the user in the typical human tasks such as managing accounts or write a text.Application software include database program,word processor,and spreadsheets.


COMMUNICATION DEVICE
Terminal used to send video or text mobile phones, wireless PDA's and personal computer equipped with microphones,speakers and cameras are all considered communication device



COMPUTER
- A programmable machine
-A device used for computing ;spesific, an electric machine which, by means of stored instructions and information, perfoms rapid, often complex calculations or compiles, correlates and selects data.



DESKTOP COMPUTER
A desktop computer is an independent personal computer (PC), as opposed to smaller forms of PCs, such as a mobile laptop. Prior to the wide spread of PCs a computer that could fit on a desk was considered remarkably small.



EMBEDDED COMPUTER
-Small computer that works out info for other things ex, mobile phones, ATM, microwave, CD players, cars etc
-Special purpose computer system designed to form one or a few dedicated functions, often with real time computing constraints


GRAPHICAL USER INTERFACE
Is a type of user interface which allows people to interact with electronic devices like computer , hand-held devices (mp3), household appliance and office equipped.


HARDWARE
-Is the physical part of a computer, including its digital circuitry, they are hard in sense that they are infrequently change
-mechanical & electronic component of computer for example motherboard,optical drive ,monitor mouse,keyboard etc.


INTERNET
A global network connecting millions of computer more than 100 countries are linked to exchange of data, news and opinions


INSTALLATION
Work of art requiring construction or elaborate setting up at its exhibition site: an installation typically makes use of a variety of of media and often include.


NETWORK
-A group of two or more computer systems linked together.
-Is a series of points or nodes interconnected by communication path.Networks can interconnected with other network and contain subnetwork.