Logical File System and Physical File System - Assignment Example

Information Technology PART I Constant Angular velo as applied to disk drives This refers to the technique for accessing data from rotating disk drives. The rotation speed is constant and is independent of the area being accessed. CAVs are easy to design and produce. Priority based interrupt controller PIC major function is to set interrupt requests into a hierarchy. When a request of certain priority is served, the servicing cannot be interrupted by requests of the same or lower level. Only higher levels of interrupts can suspend the servicing of interrupts at lower levels. Direct Memory access This characteristic of computerized systems permits certain subsystems to access the main system memory independently of the central processing unit. Graphic Processor Unit This refers to a computer chip that performs rapid arithmetical calculations. Primarily, the purpose for these rapid mathematical calculations is rendering images. It is abbreviated as (GPU). Hard disk latency The time taken for the selected sector to take position on the write/read head best explains hard disk tendency. It is also defined as the duration to instigate and effect a request. Moreover, it is highly depended on the time taken between the query and the output. PART II A common DVD-ROM read speed is 18-22X Standard speed would be 10.5MB/s or about 1.3MB/s Find its product with 18; it will be 23 MB/s 4.5 GB = 4600MBs at 23mbyte/s, it will be 4600/23 Therefore; 4600/23 =200 seconds For a motion picture image, it may be necessary to change every pixel in the image as many as thirty times per second, although usually the amount of change is somewhat smaller. This means that without data compression or other tricks that a large number of pixel values must be moved from main memory to video memory each second to produce moving video images. Assume a video image on the screen of 1 1/2? 2? With a pixel resolution of one hundred forty dots per inch and a frame rate of thirty per second. Calculate the required data transfer rate necessary to produce the movie on the screen Display resolution: 1024 x 768 size by color (16bit) = 1024 multiplied by 768 by 2 bytes for every pixel this is an equivalent of 1572864 bytes or 1536 KB and 1.5 MB in other measures a) How large a video memory is required to store a 640, 480 image during display. 640 x 480 = 307200 pixels in a 640x480 image... since 1pxl serves 3 b for a 24 bit environment, thus, 921600 bytes is required. (921600 bytes=900 kb b) A 1600, 900 image? 1600 x 900= 1440000 pxls in a 1600x900 image... since l = 3 b (24 bit), therefore, 4320000 b is required. (4320000 bytes=4218 kb) 4. One line has 75 characters. Therefore, one line would be 16 bytes multiplied by 75 which is 1200bytes One page therefore would be 1200 by 40 lines which is 48000 bytes 48000 bytes will be 0.048 MBs since 1000000bytes equals 1MB If a 0.048MBS is one page then, 600MB will be (600x1)/0.048 =12500 pages 5. The range of integers was −32,768 to 32,767. Thus a 16 bit computer could access 64 bytes of accessible logic memory at a go PARTIII USB and FireWire Although high-speed USB 3.0 runs higher than FireWire 400, FireWire Generally outperforms USB. USB was designed for simplicity whereas FireWire was built for performance. FireWire has a relative speed of 400Mbit/s opposed to USB that has 240Mbit/s. Raster graphics and vector graphics As much as the difference between these two is never felt on the finished product, Raster graphic are made of pixels while vector graphics are made of paths. Raster graphics include file extensions such as .jpeg, .gif and .png while Vector graphics include .psd files amongst other grid or curves compiled files. Vector graphic are considered the best. Parallel ATA hard disk interface and Serial ATA hard disk interface. In performance, Serial ATA will provide a 150MB/s of throughput to each drive within the array. As opposed to parallel ATA whose connection is much slower and does not spread through the arrays. SATA is independent of BUS sharing in its topology. Parallel ATA connection is about 80MB/s and is dependent on the bus sharing thus relatively slow. UNIX and Linux LINUX is secure and readily available while UNIX has threats (viruses) roughly 100-85 that are in continuous circulation. Linux is applied on a different range of platforms unlike UNIX where all functionalities are restricted to one array. Linux is relatively cheaper than UNIX and has easier bug fix protocols Logical file system and physical file system Physical files are a collection of bytes stored in a disc or tape. Logical files however, are a channel that encrypts a file’s location and format to a program. Physical files must have a logic address and this makes Logical easily accessible by the processor. Nonetheless, physical files are preferred on UI applications, as no user would find it easy to access file paths in logics. PART IV because dumb computers access data from the CPU and DMA means Direct Memory Access Typewriter-type printers jammed a lot the printing ball was too slow why they went extinct. Multiprogramming I the ability of a system to execute variable program codes at one go whereas multi user refers to ability of a system to have more than one user at a go. However, Multiprocessing is the ability of a system to compile several processes simultaneously. When virtual storage is used for memory management, program relocation is unnecessary since all the process occurs at a virtual path within the processor. A MOVE operation from one device to another requires manipulation of the file itself due to the reference in memory directory. The operations are somehow stored in the same drive unlike a MOVE operation from one place to another on the same device which definitely involves manipulation only of the directory. PART V In computer programming, piping refers to boosting a processors performance by breaking the fetch execute cycle. It occurs when each stage is occupied with a unique process. Piping is common within UNIX platforms and it enable breaking of cycles into various stages (fetch, decode, execute). It brings about even faster multitasking, the process are dealt with at the various stages created by the piping. Disc caching helps in the speeding of disc access. Therefore, if it were to have strategies aimed at improving system performance, they either would directly or indirectly involve disk access speed. Several strategies could improve system performance. Having an external disk cache is one of these strategies; this will reduce the memory and information pile up on the ram and another part of the memory as opposed to internal cache b. A computer structure has a primary memory and a write back cache memory, which has I/O devices that enable it stream data. A controller responds to signals created by the input devices and relays the sequences to an output device. However, these write backs can either be blocked or allowed into the I/O devices. One way of doing this is by a flushed cache line, where potential write over of information is flushed. The opposite happens when the overwrite is enabled. Deadlocks There are four known ways of handling deadlocks. First, deadlock Prevention or avoidance where the system is not allowed to get into a deadlock state. This can be achieved by preventing at least one of the four required conditions namely; joint segregation, hold and wait, no Preemption and circular wait. Its main advantages are it has shared files that do not lead to deadlock. However, resources such as sophisticated output gadgets highly depend on exclusive access through a single process. Secondly, there is the Deadlock avoidance. The general idea behind this deadlock is to hinder any possibility of deadlocks. This is achieved by prevent at least one of the conditions mentioned in Deadlock Prevention.It requires more information about each process, and reduces the device utilization. Therefore, deadlock prevention has a more conservative approach. It even dictates the number of resources a process utilizes. The number of available allocated resources declares allocating a resource state. This shows the maximum number of processes in the system. Thirdly, there is the deadlock detection. Incase deadlocks are not avoided; this approach detects their location in the processes and somehow attempt to or totally recover. These deadlock algorithms assist the user to curb any damages that might come because of unavoidable deadlocks. Operating systems with this OS tend to be more secure and less prone to system failures. Finally, there is the Circular wait deadlock. Here, a set of processors must exist such that every processor is waiting for an input from the other processors in the set. It is an easier to use the version of Hold and Wait Deadlock Algorithm. This is because the processors are considered separate thus less effect on the process running. PART VI 1. UNIX users generally d)Believe that cat dog | grep greyhound | less makes more sense than opening a window with the dog file in it and doing find greyhound. Read More