The number of sectors may be different depending on the density of tracks and the drive type. For example, the track floppy drives can hold from 8 to 36 sectors, and track the hard drive – 380 to 700. Sectors that are created using standard programming format, have a capacity of 512 bytes, but it is possible that in the future, this value will change.

The numbering of sectors per track begins with unity, in contrast to the heads and cylinders, which is counting from zero. For example, a floppy disk HD (High Density) format 3.5-inch (1.44 MB) contains 80 cylinders, numbered 0 to 79 in the drive has two heads (with numbers 0 and 1), and each track is divided into the cylinder at 18 sectors (1-18).

When you format a disk at the beginning and end of each sector are additional areas to record their numbers, and other service information, through which the controller identifies the beginning and end of the sector. This allows us to distinguish an unformatted and formatted the disk space. After formatting the disk capacity is reduced, and this has to be reconciled, as to ensure normal operation of the drive for a disk space should be reserved for official information.

At the beginning of each sector recorded its title (or a prefix – prefix portion), that determines the beginning and the sector number, and in the end – the conclusion (or suffix – suffix portion), which contains a checksum (checksum), necessary to verify data integrity . Most new drives instead of the title, so-called entry No-ID, accommodating a larger amount of data. In addition to these areas of service data, each sector contains a data area of 512 bytes. When low-level (physical) formatting to all data bytes assigned a value, for example F6h.

In storage rings are usually installed multiple drives, and data is written on both sides of each of them. Most drives have at least two or three discs (which can record on four or six sides), but there are also devices that contain up to 11 or more disks. The same type of (equally spaced) on all sides of the track drives are combined into a cylinder. To each side of each disc provides its own track read / write, but all the heads are mounted on a common shaft or a rack. For this reason, the head can not move independently of each other and move only synchronously.

Hard drives spin faster than flexible. The frequency of their rotation, even in pain in most of the first models was 3600 rev / min (ie 10 times more than in the floppy disk), and until recently was almost a standard for hard drives, but now speed drives increased, for example, on my laptop drive capacity 3.3 GB rotates with a frequency of 4852 rev / min, but there are models with frequencies 5400, 5600, 6400, 7200 and even 10 000 rev / min. The rate of work of a hard drive depends on the frequency of its rotation, the velocity of the system heads, and the number of sectors per track. In addition, due to a combination of all these factors to communicate with hard disk drives is much faster than floppy disks.

The third disadvantage of raster images – a large amount of storage space on your computer. There is also such that, when working with raster images of high definition could not handle users’ computers, and the size of such masterpieces of the hundreds of megabytes.

The second drawback of bitmap – no internal structure. Try to understand the example. For example, we have a drawing machine, and we need to “tear” at the car door. As a result of erasing the door, formed a “hole”.

When working with vector images , most problems disappear. In order to reduce vector image , you need to change only one control parameter is the size of the image. After zooming in, the file size does not increase at all. vector image , has an internal structure, so we are erasing the car door, do not get a hole, and the Vice-then this will be visible to the machine shop.

Below I give you a sign for comparison of computer graphics that vividly reflect the essence of this article.

Types of Computer Graphics

In addition to these kinds of computer graphics , are:

• Fractal – Fractal minimal element.
• Engineering Graphics – Graphic editor Auto CAD.
• 3D graphics.
• Interior design.

On this I finish this article, I hope you are completely finished with raster and vector images.

A vector image is a set of more complex and diverse geometric objects (circles, ellipses, rectangles, polygons, line segments and arcs of curves). An important feature of vector graphics is that for each object (class of geometric objects) are defined by control parameters (color, size), specifying its appearance. The computer is a vector image as a list of all the objects that make up the image.

Find the example of a vector image in life is not easy. But imagine the picture painted by many geometric shapes. In the school program vector images is, graphs of functions.

The output raster image on a screen or paper as opposed to simple vector images. Devices that output vector images known as plotters. The process of converting vector images into pixel image is called rendering. Rendering – the merger of screening layers without storing the result in the file.

The very first Cathode ray tube(CRT) displays applied to personal computers were definitely simple by- current standards; this CRT showed just textual content in just one color (normally green), however this will help computer users during the time with excellent upgrade, providing real-time display screen associated with input and output computer data. As time passes, coloration monitors are launched, display screen dimensions increased, along with Liquid crystal display(LCD) technological innovations migrated from a mobile laptop to the desktop computer. The newest designs, LED monitor, large-screen plasma display panels  and LCD/DLP projectors, indicate the growing convergence for multimedia and computer system technologies, it shown by developments for example Microsoft Windows Xp Media Center PCs.
These days, Computer monitor computer  are much more innovative, however, you should be aware when choosing video hardware  . A bad display screen causes eyestrain or perhaps dramatically reduce the experience of  your Computer system.

The video subsystem for a Personal computer contains 2 primary components:

• Monitor (also known as computer display). The computer monitor is usually a Cathode ray tube(CRT) or an Liquid crystal display (LCD) panel suitable for desktop computer , or perhaps a wide-screen Lcd Television, plasma display, or even projector applying Liquid crystal display or DLP technology.

• Video adapter (also known as the video card or graphics adapter). For numerous the latest low-cost desktop computer systems and practically all mobile systems, video adapter can be included in any mainboard  and as part of  mainboard’s chipset. For a computer’s desktop, you can add a high-speed AGP or PCI-Express video adapter for better display view even  3 D application.

Both of them AMD and Intel launched dual-core x86-compatible desktop computer processors during 2005. AMD’s entrythe Athlon 64 X2 can easily be placed in lots of Socket 939 mainboards made for the first single-core Athlon 64 or even Athlon 64 FX processors. An important BIOS update is probably required in common situations. AMD as well released dual-core variations of the Opteron workstation and also server processor chip around 2005. Intel’s earliest dual-core processor chips the actual Pentium Extreme Edition and also the Pentium Duse exactly the same Socket 775 as being the newest Pentium 4 versions. But, they need brand new mainboards with the Intel 945 and 955 series chipsets or maybe third-party chipsets which compatible dual-core operation.

Hard disk heads and platters.

A hard disk drive consists of solid, disk-shaped platters, normally made of aluminium or possibly glass (look at picture). Not like diskettes, this platters cannot bend or flexhence the term hard drive. For most hard disk drives, you cannot take off the platters, and that’s why they’re often known as fixed disk drives. Extrenal harddrives are offered also. Generally, this kind of term describes a device where the whole hard drive device (that’s, this disk unit that consists of a platters along with the entire drive) is removable, however it may also refer to cartridge drives, in which the platters usually are built into a removable cartridge.

Note :

Hard disk drives in many cases are known as Winchester drives. The following term goes back to 1973, once Ibm released the type 3340 hard drive, that have 30MB of fixed platter together with 30MB of detachable platter storage with individual spindles. The particular drive was initially codenamed Winchester by project leader Ken Haughton because the original total capacity designation (30-30) seemed just like the well-known .30-30 (caliber-grains of charge) cartridge applied by the Winchester 94 rifle launched in 1895. An original 3340 “Winchester” drive appeared to be the first one to work with a closed head/disk assembly, and also the name has since been used on all of subsequent hard drives using the same technology.

• The ISA bus, which is an older low speed bus.
• The PCI bus, which is a new high speed bus.
• The USB bus (Universal Serial Bus), which is a new low speed bus.

As mentioned earlier, I/O busses are really derivatives from the system bus. On the system board it ends in a controller chip, which forms a bridge to the two other busses. The essential in modern PC’s is fast busses. Let us compare the two primary I/O busses:

Clearly, there is a vast difference between the capacity of the two busses. All in all, the busses have a very central placement in the PC’s data exchange. Actually, all components except the CPU communicate with each other and with RAM via the different I/O busses. Here you see a demonstration of this logic:

• The system bus, which connects the CPU with RAM
• I/O busses, which connect the CPU with other components.

The point is, that the system bus is the central bus. Actually, it connects to the I/O busses, as you can see in this illustration:

You see the central system bus, which connects the CPU with RAM. A bridge connects the I/O busses with the system bus and on to RAM. The bridge is part of the PC chip set.

3 different I/O busses
The I/O busses move data. They connect all I/O devices with the CPU and RAM. I/O devices are those components, which can receive or send data (disk drives, monitor, keyboard, etc. ). In a modern Pentium driven PC, there are two or three different I/O busses:

• The ISA bus, which is oldest, simplest, and slowest bus.
• The PCI bus, which is the fastest and most powerful bus.
• The USB bus, which is the newest bus. It may in the long run replace the ISA bus.

BIOS is a typical link in the IBM compatible PC design. The BIOS programs control hardware, the user (programmer) controls hardware via a call to BIOS.

BIOS typically occupy 1 MB, and the programs are saved ROM chips on the system board.

During start-up, BIOS is read from ROM chips. That information is supplemented with the system data saved in CMOS. Furthermore, there is BIOS code on the expansion cards. The expansion cards are external hardware, as interpreted by the system board, and the BIOS code, which is linked to the expansion card, must be included in the configuration.

Therefore, this expansion card ROM is read during start-up, and the program code is woven together with other BIOS data. It is all written into RAM, where it is ready for the operating system, as you can see here:

Otherwise, the BIOS routines are not always in use. They can be regarded as basic program layers in the PC. Many programs routinely bypass BIOS. In that case, they “write direct to hardware”, as we say. Windows contains program files, which can be written directly to all kinds of hardware – bypassing BIOS routines. One example is the COM ports. If you use the BIOS routines connected with them, you can transmit only at max. 9600 baud on the modem. That is insufficient. Therefore, Windows will assume control over the COM port.