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It is very key to check a used personal thoroughly before buying it as it might lead to problems in the future. A hard drive will not show any outward signs but might be deteriorating. The same way the needle can suddenly slip and can cause scratches on the disc ultimately leading to memory loss as used personal can fail any time. If they are checked, the faults which might occur can be known. Let us 1st see the possible faults which might occur while purchasing a used computer.
Hard disk failures can happen due to heavy wear and tear over a period of time. The read and write heads of a hard disk are used to retrieve or recode data stored on the hard disk with the help of a disk platter rotating at a high speed. Over a period of time the risk of failure or malfunction of disk increases. Faulty sectors of the hard disks can be found out only if a full surface scan is done on the used computer. The scanning time depends on the capacity and size of the hard disk of the used computer. Many skip this procedure due to the time consuming process of scanning the entire disk and end up purchasing a used personal with a faulty sector.
Monitors require to be checked for any faults. The malfunctioning of a monitor is called a “dry joint” which results in the monitor not working after getting warmed. This can be checked only if the monitor is made to work for at least 20 to 30 mins after switching on the computer.
Next is to look for any possibilities of the central processing unit getting freezed. Normally all the central processing units have a fan and heat sink for keeping the unit cool. Over a period of time the fans might not work properly due to the accumulation of dust and dirt resulting in over heating of the central processing unit and even leading to stopping from functioning. While buying a used personal the fan needs to be checked and if any abnormal sound is heard, it is not good for purchase.
The used personal might have a higher possibility of getting crashed and freezed due to the usage of the operating system for a good number of years. There might be a cache or RAM fault due to the over exposure leading to loss of data. To increase the performance of the personal and to avoid crashing, the operating system of the used personal can be reinstalled with a untried operating system or a fresh one.
While checking the used personal for any faults, it is good to disconnect the network connection if any present before performing the tests. Also it is advisable to check the drives like the CD or DVD by opening and closing them and also playing something on the drives to see how they work. Monitors of the used personal can be checked for the resolution and brightness by trying different options of color, settings and so on. To check the hard disk size the CMOS setup can be gone through and to verify the speed of the processor, cache and RAM the pause button is pressed when it appears on the screen during the booting process. To check the booting process, the personal can be turned on and off a few times and seen how it responds. Checking ought be done to see if all the passwords are erased before purchasing a used computer.
What is Defragging?
Defragging is process done to a hard disk in order to improve performance and recover some lost disk space. Defragging is an necessary part of a PC’s upkeep as it keeps all the data on your hard disk in an easily readable order. If a hard disk is left without defragging, then over time the disk will start to lose performance and also slow reduce the available capacity to data. As you will be aware if your hard disk is running slow then this will affect the rest of the system performance, in all applications and especially in games, where frame rate is important.
How does Defragging improve performance?
When you defrag your hard disk you re-arrange the order in which the data is stored on the drive. The Computer will arrange the data so that data that belongs together and needs to be read together is in reality put in the same place on the drive. The obvious question here is why doesn’t the Computer store the data in the correct way in the 1st place? In an best situation (such as a blank disk) the Computer would do these as a 1st option. However with the amount of data being deleted and wrote to the disk all 2nd the Computer is on it is no wonder that the data can’t be stored together.
Lets have a look at an example. State you write three files to a disk all 10Mb in size the data would be all in a line all 10mb block after the other. This is how your Computer would like to store the data for maximum performance. It stands to reason that this is how you would like it to be stored as well if you wanted to search for the data. But today lets say that you determine to delete the middle file as its no longer any use to you. You today have a gap inbetween your files.
Lets say this time you write a file of 15mb in size. This file will be written in the 1st 10Mb of space and the remaining 5Mb added to the backend of the free space.As you can envision with the millions of files being written to and deleted from the disk all day, not to mention the temporary files that windows uses on a frequent foundation its not hard to envision the say in which your hard disk can be in after months of use. After a defrag in this easy example your Computer would re-arrange the disk to look as follows.
When files or indeed groups of files that belong together are stores next to all other the Computer has a much easier time locating the data plus the disk heads do not have to travel to different parts of the disk to retrieve the data required. This of course speeds up the disks performance and so in turn increases overall system performance. There are of course levels of performance gains. It becomes more negligible as you move to faster hard disks with massive memory buffers to compensate for file fragmentation however I would not ignore the problem of fragmentation, it doesn’t take much effort to defrag your disk today and then
How does defragging increase disk space?
Simply put defragging doesn’t really create any free space on your hard disk. It might appear when you look at the graphics that defrag programs show you, that the disk looks like it has more space, but all you are doing is moving data about not removing any. Any disk space gain is negligible and is caused when the defrag program puts together half clusters of data. Clusters can hold a number of files, but if not filled the next file is started at the next cluster. If a file is broken into pieces around the disk and defrag can put the file back into a single cluster, or merely save a cluster somewhere a small amount of space will be released.
Advanced Defragging
Some defragging software can go a tiny beyond merely sorting your files so they are all together. Programs such as Norton Speed Disk can also sort your whole sets of files and programs into the order that they are used. For example it can be set so that your windows swap file is at the fastest part of the disk, followed by games and most used applications which also require the fastest part of the hard disk., Then documents etc and rarely used application can be put to the back of the disk., This gives the priority speed access to the applications that require it most. Again this might only be a small increase in performance but all tiny helps.
Software to use for Defragging
You will be pleased to know that Windows comes with an sufficient defrag program which everyone can use. There are also some other pieces of software out there for a more particular use. Norton Speed disk is 1 option on the market which comes as part of Norton Utilities and Norton Systemworks. Doing a search on Defrag software on your favourite search engine will give you some options of free to use and pay for software.
Since the mid 90’s we have seen the birth and growth of a connective technology called Universal Serial Bus (USB). Originally designed to connect personal and telecoms equipment, it has slow become the primary means of connecting a entire host of other devices and has made important contributions to today’s IT world.
The sheer number of USB products on the market now is merely staggering, from mice and keyboards, modems, external hard drives to USB fans, lights and coffee cup warmers! Most external personal related devices now connect to a personal via a USB port. So it’s no wonder that before long, most personal users obtain themselves wondering what to do when the USB ports (sockets) on their personal are all used.
There are 2 answers to the problem, constantly plug and unplug connectors when swapping between USB devices, or invest in a simple, low price device called a USB Hub. A USB Hub is a small unit with 2 or more USB ports, which plugs into an USB port on your computer, allowing you the freedom to connect more USB devices without disconnecting others. Expanding the number of USB ports of your personal in this way not only saves wear and tear on your USB ports and connectors, but also puts and end to all that clambering around behind your PC! Generally speaking, there are 4 types of available:
1. Internal USB PCI Card
An internal PCI USB Card needs to be installed by opening up the case of your Computer and inserting a card into a vacant PCI slot on the motherboard, this type of USB expansion is not advised unless you are familiar with working with and inside computers. If you have the older USB1.1 and upgrade to USB2.0, your variation of Windows will also require to be updated so that your Computer can support USB2.0 functionality.
2. USB Hub (Non Powered)
An external non-powered USB Hub is a cheap and easy device that plugs directly into 1 of your computer’s existing USB ports and that is all there is to it. These are usually very compact and so make ideal answers for mobile users with laptops and for desktop users.
Be aware that some USB devices require a small amount of power through the USB port, usually mechanical devices such as printers, scanners, digital cameras and so on. This type of USB Hub might not be capable to supply sufficient power to these devices especially if you are using a few USB devices together.
3. Powered USB Hub
An external Powered USB Hub is also compact and plugs directly into 1 of your computer’s existing USB ports, so again there is no require to open up your personal to install it. The only difference is that the Powered Hub comes with a separate power supply that must be plugged into the mains socket, supplying the power to all the USB ports on the hub allowing ANY type of USB devices to function properly.
Most Powered Hubs come with a sensible length of USB cable allowing the Hub itself to be positioned in a more accessible place e.g. on top of your personal or on your desk, making plugging and unplugging USB devices much easier. This makes the Powered Hub the all round ideal solution for desktop personal users.
4. USB Computer Card
If you use a Laptop and are on the move, you have an additional choice to the USB Hub, the USB Computer Card also known as the PCMCIA USB Card. This device slots into the PCMCIA slot/port found on the side of a Laptop and instantly provides 2 additional USB ports without using up any of your existing USB ports on the Laptop.
This is the most common solution for mobile Laptop users. When buying a suitable external USB Hub, think about the location of your computer’s USB ports. If they are located at the back of your personal or in an awkward position, you can make your life so much easier by using a USB Hub that comes with a USB extension cable, or by buying a separate USB extension cable. This lets the USB Hub to be positioned to a more accessible place for plugging and unplugging your USB devices.
USB flash drive or any other flash memory drive is basically an EEPROM that means “Electrically Erasable Programmable Read Only Memory”.
USB flash memory sticks are nothing but an assembly of EEPROM, a controller with a RISC microprocessor, RAM and ROM. All of this interacts with a personal using a USB controller and connector.
Because USB sticks are EEPROM these can hold data for as long as ten years. As these memory modules are shock proof and as these do not have a volatile memory are good enough to sustain shock and humidity to some extend that is casual abuse that includes run through a washing machine, or even dropped in coffee.
UBS thumb drives normally do not require drivers but with few old operating systems like Windows 98 and Windows 95 you require drivers that are provided by the manufacturer. Latest OS think about USB drives as USB Mass storage devices and have built in support for these drives that means you do not require any drivers merely plug in the drive and begin using it.
Some Linux versions might recognize it but will not let you use it until you manually mount the drive. To mount to drive manually use the command
“mount -vfat (drive to mount) (directory to mount at)”
Eg. “mount -vfat /dev/sda1 /mnt/usbdrive”
Manufacturers are also coming up with systems that have bios support for USB that means you can boot from the small USB drive. There are different versions of operating systems coming up that can be installed on a ROM and are so small to fit a USB drive as well. Most of these OS versions are Linux based for example Damm Small Linux.
USB drives are mainly used to carry personnel data. But you require to be very careful with your personnel data today days. You can have anything in your personnel data collection that you have forgotten for example bank account details or anything. Try using some encryption engine to secure your data. You can use encrypted file system over the USB drive but then you will be capable to access your drive only at few personal not all. Or you can have a encryption application that can run without installation from your USB. The ideal would be to use biometric USB drives.
For the past 10 yrs USB and FireWire have struggled to dominate the desktop interface market. Until five yrs ago, because of the relatively fast 4 hundred Mbps offered by FireWire, USB, jokingly referred to as Ultra Slow Bandwidth, was relegated to low-bandwidth applications such as keyboards and mice. At the end of 2001, however, USB dealt a fatal blow to FireWire with the release of the untried USB 2.0 standard offering a maximum speed of 480 Mbps, faster than the theoretical limit of FireWire (though, in practice, usually slower).
It seems that USB has essentially won the standards battle with FireWire because of its relative low-cost and high availability. The limitation of USB (both the 1.1 and 2.0 standards basic today) is the 16 foot limit. When you have more than 16 feet between your personal and your USB device you will see important degradation in the signal that can cause problems ranging from slower transmission speeds to an entirely dropped connection. This causes problems for people who desire to run a USB cable to a printer located in another room, to a presentation keyboard/mouse combo or any other USB device that might be in a remote location.
The cheapest (and arguably easiest) way to extend the distance to your USB device is by using a USB Active Extension Cable. These cables have built-in USB repeaters that in reality boost the USB signal, allowing you to go further than the 16 foot maximum distance. The most basic length for these cables is 16 feet and you can chain up to 4 of these together with no loss in signal. Assuming you are using the longest USB device cable available (also 16 feet), USB Active Extension Cables grant for a maximum distance of 80 feet between your personal and USB device. They are available in USB 1.1 (12 Mbps) and USB 2.0 (480 Mbps).
For most USB extensions 80 feet is long enough, but what if you require to go further? Super USB Extenders grant you to extend the distance to your USB devices up to 150 feet with no loss in signal. The Super USB Extender uses similar technology for the male and female interfaces, but rather than have a regular USB cable in the middle, it uses a Cat five cable (also known as a networking cable). The advantage of Super USB Extenders, other than the increased maximum distance, is the capability to create a custom length. If you require to go 63 feet, for example, you can simply use a Super USB Extender with a 63 foot Cat five Cable between the booster and receiver. Super USB Extenders are also available in USB 1.1 and 2.0 interfaces.
If you are looking for a connection beyond 150 feet, numerous manufacturers offer a special Super USB Extender able of USB transfer with no signal loss at 330 feet, though this is restricted to USB 1.1. Black Box has produced a USB 1.1 extender able of transmission up to 1000 feet without signal loss, perfect for connecting your personal to a security camera or webcam hundreds of feet away from your computer.
Another exciting innovation for USB extension technology is the pending release of Wireless USB. Wireless USB hubs and devices are anticipated to show up in early 2006 with maximum distances over one hundred feet. Keep in mind that this is the 1st release and as the technology matures this distance limitation will inevitably be lifted in favor of much further distances.
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