342

Available data storage capacity for RAID5 is 2.5TB (2500GB)

2.5 bam 5

The Operating systems typically handles cache memory by:

A memory handler

What are three methods to obtain an embedded OS?

Adapt an existing OS to embedded application, Select an existing embedded OS, Design a unique embedded OS

The operating Systems real customers are the:

Application program

How many hard drives are needed in order to create a mirror set?

At least two or add more but in pairs , must be an even number of hard drives.

Consider a system with a total of 2300 MB of main memory , allocated to three process as shown

Available: 2300 - 1200 = 1100 MB Process B Free memory is 1100 MB A needs 650 MB so this can be done and old memory will be released|Available: 2300 - 400 = 1900 MB Process C Free memory is 1900 MB A needs 320 MB so this can be done and old memory will be released |Total Memory Allocated: 240 + 800 +400 + 810 = 2250MB Total Free: ( 2300 - 2250) = 50 MB |Process A Free memory is 50 MB A needs 650 MB so this CANNOT BE DONE Process B Free memory is 50 MB A needs 120 MB so this CANNOT BE DONE Process C Free memory is 50 MB A needs 320 MB so this CANNOT BE DONE Process D Free memory is 50 MB A needs 90 MB so this CANNOT BE DONE D cannot be granted there is no safe sequence of execution in present state due to not enough MB space

Available data storage capacity for RAID1 is 0.5TB (500GB)

BITCOIN #1 0.5 im rich

Each location in main memory contains a ______ value that can be interpreted as either an instruction or data

Binary

A disc scheduling method that stops at needed tracks in a single direction is:

C-SCAN

What are three issues of a distributed system?

Concurrency Synchronization Independent Failures

A _______is several computers that do not share a common memory of clock.

Distributed System

An ______ is the use of electronics and software within a product to perform a dedicated function.

Embedded System

Lab Question: Choose either windows or Linux or Other( if applicable) Please circle the type: Linux: What is the difference between a process running in the foreground a process in the background?

Foreground processes refer to applications you are running that you are currently interacting with, and which applies equally to graphical user interfaces as it does to the command line. Background processes refer to applications that are running but not being interacted with by the user.

How can an instruction trace be used?

Generally utilized to determine distribution of instructions, identification of register dependencies, branch path analyzes and timing.

When compared to a centralized system, a distributed system:

Is more autonomous across a wide range of technology

The concept of multiple programs taking turns in execution is known as:

Multiprogramming

Briefly explain why computers have O/S. in which situations would an operating system not be wanted on a computer.

Operating systems help generalize the hardware from the user (application programs). This allows the programs to be written to be used across many machines instead of just one. An OS also allows for upgrades and fixes to be installed without the need to change the application programs. If you have a system that needs greater performance, then an OS could push the performance past the point of usability.

Why would you want an OS for an embedded system?

Optimize and make efficient use of hardware, provider user with convenience and user friendliness, Hide the complexity of the computer hardware, provide the ability to evolve. (Same as any other OS) what is embedded systems?

Which of the following scheduling policies allow the O/S to interrupt the currently running process and move to the Ready state?

Preemptive

When comparing RAID0, RAID1, RAID5 and RAID6, which ones provide a redundant (redundancy) solution?

RAID5 because the load can be shared over a number of disks. It has gotten far faster than RAID 1 overtime.

_____________of a disk involves the movement of the disk head and the time it takes for it to settle to a stop.

Seek Time

Explain a difference between Single , Double and Circular Buffer.

Single buffer is the simplest type of support om a I/O request it assigns a portion of main memory to the operation. Double buffering occurs by assigning two system buffers to the operation. A process transfers data to one buffer while the OS fills or empties the other. Circular buffer is a buffer with two pointer such as read and write . When both pointers are equal the buffer is empty.

Each of the following are considerations you would use in selecting a secondary storage management system EXCEPT:

Size of Software

What is the difference between spatial and temporal locality? Be specific and cite examples.

Spatial locality refers to the tendency of execution of memory locations near each other. Temporal locality refers to the tendency of execution to access locations that have been recently used. Temporal is strong in loops and in data. Locality of reference refers to the observation that computer programs reuse data or use memory locations that are near each other and exploiting this behavior. Code heavily uses spatial locality. Loops or data calculations use temporal locality.

Two trends in I/O are:

Standardization and New Devices

If a system runs out of, _______ it may be forced to abort processes or may crash completely.

Swap Space

1. How many drivers are needed in order to create a data set?

TWO

In a uniprocessor system, multiprogramming increases processor efficiency by:

Taking advantage of time wasted by long wait interrupt handling

Consider a 6-drive, 500GB-per-drive RAID5 array. What is the available data storage capacity? Consider a 2 drive, 500GB per drive RAID1. What is the available storage capacity?

The answer should be between 1500 and 3000 GB. 1500 for mirrored, 3000 for not mirrored, in between for ECC and parity. Maybe less than 1500 for mirrored and ECC. You didn't have to say which RAID but you needed to explain what it was (mirrored for example). If you gave the RAID number and was incorrect it is wrong. The OS doesn't know there are 6 drives, it treats it as a single disk. 0: not redundant - 6 drives * 500 GB/drive = 3000 GB (which is not 3 TB) 1: mirrored - 3000 GB / 2 = 1500 GB ½ each for the calculation and the identification of a single drive.

What is the relationship to the size of virtual storage to the actual number if main storage locations?

There is no relationship between the two

Characteristics of an embedded system include all of the following EXCEPT:

Use of Polling for control

When does a page fault take about twice as long as normal?

When the page is dirty.

In your computing environment, you notice that your applications frequently get requests for many short I/O requests. Using the concepts from this course what could you do to allow a single application to proceed more quickly?

You could separate resource ownership (a process) and scheduling/execution (threads). In doing so you could execute many threads in an execution period each of which gets blocked for I/O. In the end however the process proceeds much more quickly. Since it is likely that the requests are near each other on the disk, getting them to the disk sooner can also give a performance boost on the disk scheduling as well (assuming the correct algorithm is in play)

A_____is issued if the desired page is not in main memory.

page fault

A ______ is an entity corresponding to a user job or application that owns resources such as memory and open files.

process

A_______ is a single execution path with an execution stack, processor state, and scheduling information.

thread

What are three methods of distributed system?

· telecommunication networks: telephone networks and cellular networks, ... · network applications: World Wide Web and peer-to-peer networks, ... · real-time process control: aircraft control systems, ...