Monday, December 06, 2004

Hardware Concepts

Accuracy of data input is important. What method of data input would be best for each of the following situations and explain why: (Printed questionnaires, Telephone survey, Bank checks, Retail tags, Long documents).

The some reading text would have you believe that a keyboard is the important input device for the listed items. A keyboard is best for long documents as input. For printed questionnaires a scanner as input to scan a specific type of printed survey such as the SAT tests. Voice recognition would be ok for a telephone survey, but still prove to be very inaccurate as input. Telephone surveys are best using the telephones keypad. A specialize bar code scanner for Bank Checks is best as input. A regular bar code scanner found in most shopping centers provides the greatest degree of accuracy as input.

Convenience and quality of output are important. Explain what method of output would be best for each of the following situations and explain why: (Hand held computer, Color photograph, Resume, Memorandum, Statistical report, Company annual report).

This question does not state the purpose of the output. The purpose of the output is changing each day as technology advances. Old ways are morphed into new methods and better management of the data that is outputted. The reading text would lead you to believe that a printer or monitor is best for these items as output.

For a handheld computer the most common method output is a small LCD screen either monochrome or color as output.

A photograph is dependant upon the output intent. Is the photograph for a web site, a database, a printed magazine or for a holographic image? If it is for a picture frame, then a high resolution printer is best to print a photograph that is an electronic high resolution as output.

In the past a standard laser printer would have been best for output of a resume. Today with online databases systems prefer a particular input format of the data from the resume so it maybe disseminated to a large number of potential employers. Tomorrow resumes will be in an XML format to allow seamless integrations with any online job hunting service. For today and tomorrow a monitor either a CRT or LCD is best for a resume as output.

Today many companies have abandoned the old paper memorandums for well formatted emails. Some companies require electronic signatures and encryptions for memorandums. An LCD or CRT is best to view today’s memorandums as output.

Statistical report output is dependant upon who the audience is. A scientist, stock broker or accountant would prefer an LCD or CRT as output. Where as a CEO, board member or the general population that might not have access to a computer would prefer printed stats on paper as output.

Today most company’s annual reports are available online on their websites. However there are a great many that still spend $1,000’s of dollars on glossy paper annual reports for the board members and investors. For the website and LCD or CRT is best for output. For printed reports a commercial based printer is best for output.

Explain the difference between primary storage and secondary storage.

Some text states: “Primary storage is temporary storage, and anything stored in it is lost when someone turns off the power to the computer. Secondary storage, however, is permanent storage; anything stored in secondary storage remains there until the computer changes it, even if someone turns off the power.”

To better understand RAM (Random Access Memory) it is the fastest place to store and retrieve data. On page 13 of the Course Notes it implies that RAM is the primary storage area for the computer. It is the preferred and most common method. It is not the primary area for storage as there are many devices that have RAM such as video cards, network cards, fax cards, the CPU has memory called cache, hard drives have cache and hard drive controllers like a RAID 5 card have cache. These devices also contain firmware that are flash updatable. Your hard drive is the preferred area for permanent storage of data, but not exclusive. RAM is only useful while the computer is turn on. Once the computer is turn off all data being kept in RAM is lost. During the boot process data is read from the hard drive and loaded into RAM most commonly called "memory". The data is kept there for fast access and processing. When things in "memory" get really corrupted, rebooting is the only way to clean out the RAM of the bad data. A cold reboot is preferred. A cold reboot is powering off the computer, wait one minute and power it back on. A warm reboot is just a simply restart. That is fine for the OS but some hardware issues require and cold boot. While the author of reading text calls “memory” primary storage, this is incorrect.

Different types of storage devices are optimal for different situations. Explain what situations are appropriate for the following devices and explain why: (Hard disk, Floppy disk, RAM, CD ROM, Tape).

Floppies, CD-ROMs and Tapes are old school portable media that are quickly being replaced by portable hard dives, and Jump Drives. Most computers today do not have floppy drives or CD-ROMs any more when you go to make a purchase. They are replaced by DVD-/+RW ROMs and Firewire and USB 2.0 devices.

The hard drive is the primary area that the operation system is installed. Most data used by the user is stored on the hard drive. It is the fastest permanent storage media with the highest capacity.

RAM (Random Access Memory) is where information is temporary stored for fast access. It is faster than a hard drive, but it is costly and has less capacity for storage. It has no ability to permanently store data without the aid of battery backup or a secondary power source to keep data alive while the computer is turned off or suspended.

Tape is still commonly used for backup systems, but is quickly falling out of favor for that usage as portable hard dives decline in cost and increase in speed and capacity. Tape Drives have not been able to keep up with removable hard drives in these areas.

Explain the role of each of the following in determining the speed of a computer: (RAM, Clock speed, Data on hard disk, Data on CD ROM, Data on floppy disk).

In today’s computers there are many things that can affect performance or the speed of the computer. These are called bottlenecks.

RAM can be a bottleneck if the bus speeds are faster that the speed of the memory. In the old day’s memory used to be measured in nanoseconds such as 80, 70, and 60ns memory. Today they are measured in clock speeds of PC100, PC133, etc. There are also many difference types of RAM that the reading text has not bothered to talk about that are contained on other devices like the video card and the CPU called cache.

Clock speed is typically referred to as the speed of the CPU. Today other devices have clock speeds such as the video card. The clock speed of the CPU used to be an indicator of how fast the CPU was as compared to other CPU’s. That is no longer the case. The type of CPU is more important to know now rather than the clock speed. For example a Pentium M 1Gig processor is faster than a Pentium 4 1.8Gig processor. So clock speed doesn’t count any more. You have to use a comparison or benchmark chart to figure out which processor is faster.

The “Data” on a floppy or CD-ROM has no bearing on the speed of the computer. The speed of the floppy drive or the speed of the CD-ROM has an affect on the speed of loading/reading data from the media. A floppy drive is by far the slowest device of reading and writing data.

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