Study Guides (238,098)
Canada (114,918)
York University (9,812)
ITEC 1000 (17)

Itec1000 examreview

6 Pages
Unlock Document

York University
Information Technology
ITEC 1000
Peter Khaiter

Lecture 11  DMA is a problem with multiple cpu’s.  To improve system performance in a computer o Multiple cpus o Faster clock speed o Wider instruction and data path o Faster disc access o More and faster memory  Multiprocessing increases parallel processing o 2 types are Tightly processing:Each system has its own cpu, each sys known as a node. o Loosely coupled systems: extends multitasking and program execution  A masterslave processing is a master cpu that controls the system its simple but if it fails, the whole system does.  The OSI model was created by ISO.  OSI consists of 7 layers  Ring network topology is bus is closed no ends.Undirectional and pnt to pnt. 2mb-16mb/sec  Star is a central node does most of the processing remote nodes are connected point to point with it. Has 2 undirectional links. 1gb/s  Loop is similar to ring, nodes directly in communication path.  Hierarchical is a tree like structure  Web is everything connected to everything else.  MAC are characteristics of the channels , data , rate ,voltage lvls etc. detects errors has Ethernet and token ring.  Token ring MAC protocol token seized by changing a bit to indictate start of frame rather then token  Hub is central element of the star layout.  Point to point connectivity has 1. Phone lines 2. Cables 3. Wireless 4. Fiber optics.  Gateway communicates different networks  Bridges communicate similar networks Lecture 9-10  Peripherals are classified as Input, output, and Storage.(not the cpu,memory etc).  Access time is the time it takes to locate data and read it.  Throughput is the amount of data moved per second(always kb/s)  Primary memory is immediate access by the cpu(cached,conventenial)  Expanded storage(ram) a buffer between the cache and conventenial  The track is the circle of the magnetic disk  Cylinder is the small track on all platters  Sector is the pie shaped part of the platter  A capacity of a harddisk can be from 5mb to 1+ tb  The Winchester disk cannot contain dust particles, invented by IBM  Platter is the round surface the disk containing a magnetic coating  Track is the the circle on the disk surface in which data are contained  Head assembly is a mechanical unit holding the heads and arms  The drive motor rotates all the platters  Block is the smallest unit of data that can be written or read.  Seek time is the time for the head to move to the correct track  Latency time is the time it takes for the correct block to reach the head  Transfer rate is same as throughput  Avg.Latency time ½*1/Rotational speed  With multiblock transfers, sometimes sectors cannot be read or written consequetively , this results in lost performance. It must undergo a full revolution to the next sector. The solution? Interleaving  Interleaving basically skips one or more blocks in its numbering  Logical mapping is the way information is perceived to be stored  Physical mapping is the way information is actually stored  Removable hard discs are also called disk packs  RAID(Redundant Array of Inexpensive Discs) This is mostly used on servers  Level 0 is Data Striping, no redundancy, does not have fault tolerance but improves performance  Level 1 is Data mirroring(shadowing),one drive fails another can replace it, has fault tolerance  Level 3 same as lvl 0, reserves 1 disk for error correction data, some lvl of fault tolerance  Level 5 has excellent performance and fault tolerance, data striping at the byte lvl  Fault tolerance is the ability for a computer system to respond calmly to hardware/software failure.  Data mirroring is if one disk fails, there is another one it can switch to without the loss of data  Data striping is spreading data over multiple disks  Optical storage uses light generated lasers to record and retrieve info  CD-ROM(Compact disk read only memory) capacity of 550mb  CD-ROM speed is CLV, Magnetic disk is CAV  Harddrive magnetic, CD optical  Has about 270,000 blocks  In optical storage laser strikes land:light reflected into detector. Laser strikes a pit:light scatters  Resolution is pixels on screen, when a computer boots up it goes to VGA(480x640) first, then SVGA(600x800)  Pixel is a single point in a picture element  With 8 bits per pixel a monitor can display 256 shades of grey colors  Raster is the diagonal dimension of the screen  Slide 82 very important!!!  Pixel color is determined by 3 colors RGB(4 bits per color 16 x 16 x 16 = 4096 colors)  CRT has 3 guns shooting to the screen for each color(electron guns)  Contains vacuum tube  The color transformation table(with 16 bits) the table can only represent 64,000 colors  The 24 bit colors cannot be displayed on this table.  A raster scan is scanning and displaying each pixel  Interlacing scans the odd lines first, then goes back to scan the even ones Lecture 8  The I/0 device connected to the cpu through the I/O module  Types of I/O. Programmed I/O, Interrupt driven,DMA.  The I/O module recognized messages from device and accepts command from the cpu. Has a buffer and controls the device  I/O devices run completely from the cpu control  I/O module contains Device controller, and Disk controller.  I/O device is keyboard,mouse,printer, etc all the externals devices.  I/O configurations through data,address,control.  Programmed I/O(First Type of I/O) Connected to a pair of I/O registers in cpu bus. Transfers one word at a time. Very slow.  Polling is programmed I/O where the device is status is checked to determine if an I/O operation is needed.  Interrupt driven(Second type of I/O) Signal that causes the cpu to alter its normal flow of program execution.  Register saves in the stack or PCB  External events interrupt occurs when an external device is inputed into the computer. This req
More Less

Related notes for ITEC 1000

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.