cs180
What is POSIX
(Portable Operating System Interface Standard) A set of operating-system services.
What functions does the Kernel provide through system calls
File System Management CPU scheduling Memory management Many other operating system functions
Newer computers, especially ones that want to boot from hard drives larger than 2 TB require the use of a GPT. What does GPT stand for?
GUID Partition Table
What do System functions do for the user
Gives the user access to the OS and hardware
What is the name of the Unix-based program that i demonstrated that shows all of the system calls that are being made by a process?
strace
After installing Linux Mint (or other apt-get based distribution) on your computer (virtual or real), the first two commands you should always run to make sure your system is current are:
sudo apt-get update sudo apt-get upgrade
How large is the first set of bytes and what does it contain for the MBR?
446 bytes and it contains the primary boot loader code, with the last 6 bytes are for a disk signature.
How many bytes is the master boot record?
512 bytes
How large is the second set of bytes and what does it contain for the MBR?
64 bytes and it contains the partition table
What does CPU burst mean?
A period of uninterrupted CPU activity
What does I/O burst mean?
A period of waiting for I/O to complete
What is a Process?
A program (either user mode or kernel mode) that is being executed. A process is an active entity.
A segmentation fault is generated when
A program running in user mode attempts to access memory outside the memory segment assigned by the os
What does Thread mean?
A subprocess. A process contains one or more threads.
What is the primary difference between a system call, e.g. read, and a non-system call, e.g. printf?
A system call runs in kernel space and a non-system call doesn't
What does Multi-tasking OS mean?
An OS that has more than one process at the same time. Must have multiple CPUs or multiple cores.
What does Single Tasking OS mean?
An OS that has one process in memory atonce.
What is the primary reason for the great efficiency from write to fwrite is due to what?
Buffering
In a preemptive multi-tasking OS, the following C code fragment will have what effect on the system? While(1) ;
CPU cycles will be wasted, but the system not lock up.
What is a Program?
Code that can be executed. A program is a passive entity and generally exists as a file on the disk.
What is the most popular single-tasking operating system
DOS(Disk Operating System)
What does the computer do while in POST
Discover what devices are connected and checks if they're in working condition
What does Process State mean?
Each process has information with it such as opened files, registers in use, memory allocated, duration of execution, etc
True or False: Microkernels move as much operating system code as they can into the kernel
False
True or False: Software running in a virtual machine typically runs faster than it would on a native (physical) machine
False
The core part of an operating system that supplies the essential services is call what?
Kernel
Suppose that a computer has only one small hard drive (32 GB) that is bootable. What is the name given to the first 512 bytes (first sector) of the drive called?
Master Boot Record
What are the several states in which a process can be?
New(Created) Running Blocked Ready Terminated
After the boot loader code, the first sector of the hard drive also contains the what?
Partition Table
POST
Power on Self Test
What are the two modes of operation that most modern CPU's support?
Privileged Mode and User Mode
Computers have many different types of storage (volatile and non-volatile), each with different sizes, speeds, and technologies. Three of those types are listed below ordered by speed, from fastest to slowest. Which set is ordered correctly by speed.
Registers, cache, main memory
What does the computer do first?
Runs a self diagnostic or POST
The Application Programming Interface (API) between the operating system and the user programs is defined by a set of what?
System Calls
True or False: In a microkernel most services run as user processes
True
By default, the BIOS runs a program that is stored in the first sector of the first hard disk. What does this sector contain
The Master Boot Record
What does Pseudo-parallelism mean?
The ability for a single-CPU/single-core machine to give the illusion of executing more than one process simultaneously.
What does Parallelism mean?
The ability to execute more than one process at the same time. Must have multiple CPUs or multiple cores.
What two separable parts does UNIX consists of?
The kernel and the system programs
True or False: Microkernels communicate between modules by using messages
True
True or False: The Microkernel moves as much as possible from the kernel into "user" space
True
In the past, the clock speed of the CPU was used to determine how one CPU performed compared to another. Today, the speed is only one part that affects a CPU's performance. What other characteristic is as important or maybe more important or maybe more important for performance?
The size and speed of cache memory
What are the last the two bytes of MBR and are what are they always?
They are magic numbers and are always 0xAA55
What processes does the OS have to schedule for execution?
User processes System processes
The Windows NT kernel (Windows NT through Windows 7) has support for at least 3 platforms. What are 3 of those platforms?
Win32, OS/2, POSIX
Suppose a program accepts three short command line options, -a -b -c. What does the string that is passed to the getopt function look like if option a requires an argument, option b does not accept any arguments and option c takes an optional argument.
a:bc::
Under a Unix-based system, if a user wanted to change the permission attributes on her files, she would use which program?
chmod
What does Linux wrap most of its system calls in.
glibc, the GNU C Library