ASSIGNMENT 1-VU HAI DUONG
Contents
I.Progress test 1………………………………………………………………………………………….1
1. Explain the different memory units .................................................................................................. 1
2. What is BIOS? Describe its functions. ............................................................................................. 2
3. What is the boot sector? .................................................................................................................. 3
II.Progress test 2…………………………………………………………………………………………3
1. What are system calls? Give an example of a system call ................................................................ 3
2. What is inode in UNIX? .................................................................................................................. 4
3. What is home directory in UNIX? ................................................................................................... 4
Bibliography ....................................................................................................................................... 5
I. Progress test 1
1. Explain the different memory units
Memory unit is the amount of data that can be stored in the storage unit. This storage capacity is
expressed in terms of Bytes.
a. The following table explains the main memory storage units
S.No.
Unit & Description
Bit (Binary Digit)
1
A binary digit is logical 0 and 1 representing a passive or an active state of
a component in an electric circuit.
Nibble
2
A group of 4 bits is called nibble.
Byte
3
A group of 8 bits is called byte. A byte is the smallest unit, which can
represent a data item or a character.
Word
4
A computer word, like a byte, is a group of fixed number of bits processed
as a unit, which varies from computer to computer but is fixed for each
computer.
The length of a computer word is called word-size or word length. It may be
as small as 8 bits or may be as long as 96 bits. A computer stores the
information in the form of computer words.
b. The following table lists some higher storage units
S.No.
1
Unit & Description
Kilobyte (KB)
1 KB = 1024 Bytes
2
Megabyte (MB)
1 MB = 1024 KB
GigaByte (GB)
3
1 GB = 1024 MB
TeraByte (TB)
4
1 TB = 1024 GB
PetaByte (PB)
5
1 PB = 1024 TB
2. What is BIOS? Describe its functions.
a. What is BIOS?
BIOS (basic input/output system) is the program a computer's microprocessor uses to start the
computer system after it is powered on. It also manages data flow between the computer's operating
system (OS) and attached devices, such as the hard disk, video adapter, keyboard, mouse and printer.
b. The 4 functions of BIOS
BIOS identifies, configures, tests and connects computer hardware to the OS immediately after a
computer is turned on. The combination of these steps is called the boot process.
These tasks are each carried out by BIOS' four main functions:
1. Power-on self-test (POST). This tests the hardware of the computer before loading the OS.
2. Bootstrap loader. This locates the OS.
3. Software/drivers. This locates the software and drivers that interface with the OS once
running.
4. Complementary metal-oxide semiconductor (CMOS) setup. This is a configuration program that
enable users to alter hardware and system settings. CMOS is the name of BIOS' non-volatile
memory.
3. What is the boot sector?
a. What Does Boot Sector Mean?
A boot sector is a physical sector, or section, on a hard drive that includes information about how to
start the boot process in order to load an operating system.
b. Location of boot sector
A boot sector exists on an internal hard drive where an operating system like Windows is installed, as
well as on storage devices that you may not even need to boot from, but instead are just holding
personal data on, like an external hard drive, floppy disk, or another USB device.
II. Progress test 2
1. What are system calls? Give an example of a system call
a. What are system calls?
- In computing, a system call is the programmatic way in which a computer program requests a
service from the kernel of the operating system it is executed on. A system call is a way for
programs to interact with the operating system. All programs needing resources must use system
calls.
b. Example of a system call
Examples of Windows and Unix System Calls –
Windows
Unix
CreateProcess()
fork()
ExitProcess()
exit()
WaitForSingleObject()
wait()
CreateFile()
open()
ReadFile()
read()
WriteFile()
write()
CloseHandle()
close()
CreatePipe()
pipe()
CreateFileMapping()
shmget()
MapViewOfFile()
mmap()
GetCurrentProcessID()
getpid()
SetTimer()
alarm()
Sleep()
sleep()
Process Control
File Manipulation
Device Manipulation
Information
Maintenance
2. What is inode in UNIX?
An inode is a data structure in UNIX operating systems that contains important information pertaining
to files within a file system. When a file system is created in UNIX, a set amount of inodes is created,
as well. Usually, about 1 percent of the total file system disk space is allocated to the inode table.
3. What is home directory in UNIX?
A home directory, also called a login directory, is the directory on Unix-like operating systems that serves as
repository for a user’s personal files, directories and programs… The name of a user’s home directory is by
default identical to that of the user.
Bibliography
From < https://www.tutorialspoint.com/computer_fundamentals/computer_memory_units.htm >
From < https://www.techtarget.com/whatis/definition/BIOS-basic-input-output
system#:~:text=BIOS%20(basic%20input%2Foutput%20system)%20is%20the%20program%
20a,%2C%20keyboard%2C%20mouse%20and%20printer. >
From < https://www.lifewire.com/what-is-a-boot-sector-2625815 >
From < https://www.geeksforgeeks.org/introduction-of-system-call/ >
From < https://developer.ibm.com/articles/au-speakingunix14/ >
From < https://questioncool.com/what-is-home-directory-in-unix/ >