Mouse:
A mouse is an input device that is used to interact with the majority of programs on a computer. Older models used a "ball" that had contact with a flat surface, and contact with rollers which detected movement and moved the mouse on screen accordingly. Now-a-days mice are normally optical, a laser that points onto the surface to detect movement. They can have "scroll wheels" which allow for the user to scroll down a page at a faster rate rather than using the scroll bar on the page. Mice are a great way to interact with a GIA (Graphical User Interface) as the movement is completley controlled by hand.
Screen:
Displays images that are generated by the video output from a computer. Older screens, or "monitors", we based around a Cathode Ray Tube - a vacuum tube containing an electron gun and a fluorescent screen. Whereas newer versions are normally plasma screens, or LCD displays. For graphics, a 26" widescreen or higher is normally best to allow you to have a good overview of everything on screen.
Graphics tablet:
An input device that allows for the user to draw items on screen. The touch sensetive pad is used to draw on with a stylus and this translate onto the screen. Although most graphics tablets do not display the image directly on the touch pad itself, there are some that you can buy that come with an in-built computer screen that you can see your drawings on instantly.
Digital camera:
A camera that captures images or videos digitally by using an electronic image sensor. Most digital cameras can record sound in videos also. Digital cameras can display the image you haev just captured immediatley after it is taken, something 35mm cameras cannot do. They can store mass amounts of images on a single memory unit and you also have the ability to delete these images to free up storage space. Using digital cameras to take images for graphics editing is both convenient and efficient as it allows you to capture and access image quickly.
Scanner:
An input device that can optically scan almost any object and convert it to digital image; images, letters, notes, signatures, book pages to name a few. Most modern scanners use CCD (charge-coupled device) or CIS (Contact Image Sensor) as an image sensor.
- CCD - In a CCD chip there is a photoactive region, which is an epitaxial layer of silicon, and a region called the transmission reader, made of of a shift reader, which is actually the CCD. To capture an image, a lense projects an image and tis cause the "capacitors" to gather an electric charge in proportion to the light intensity of the image. When exposed to the image, the control circuit forces the capcitors that are charged, to send the charge to it's neighbour capacitor. This is done until the last one dumps it's charge into a charge amplifier, and then this converts the charge into a volatge. When this is repeated enough times the semiconductor is converted into a sequence of voltages which is sampled, digitalized and stored.
- CIS - Consists of a linear array of "detectors" which are covered by a focusing lens. Behind these dectors are LED lights which are uysed for illumination, these lights are typiaclly red, green and blue. Light is gathered and combined from these LED (Light Emitting Diode) lights to create a white light, this is then directed on the object being scanned. The light reflected from the document is then gathered by a lens and directed at an image sensor. This records the image based on light intensity that is exposed to the sensor.
Flash Cards:
"Flash" memory is a type of memory that can be electrically erased and reprogrammed. It is a non-volatile computer memory and is used mainly in memory cards and USB flash storage drives, it allows for the transfer of data between not just computers but other digital products. It is useful for graphics editing as it allows you to transfer your data from one machine to another quickly.
USB storage devices:
USB (Universal Serial Bus) storage devices are able to be plugged directly into a USB port on a computer and the data stored on it can be transferred directly onto the computer, or vice versa. They primarily use flash memory to store data and most devices are portable. It doesn't require rebooting after it has been attatched to the computer and it doesn't need a battery supply. You can get USB storage devices with password protection and downloadable drivers which work like patches to allow them to work with older running systems. For graphics the same applies to USB storage devices as it does to flash cards, they allow you to transfer images easily.
Hard Drive:
A non-volatile storage device that can store data that has been digitally encoded on rapidly rotating platters with magnetic surfaces. Modern day HDD (Hard Drive Disc) are mainly a sealed unit unlike older models that had removable media. HDD memory is cheap to buy compared to other types of memory - RAM or cache memory. HDD record the data by magnetizing ferromagnetic material directionally so that they represent binary code - 1 or 0. To read the data back they detect the magnetic direction of the material. Some graphic formats take up a lot of memory, so if you're going to be making loads of different formats you are going to need a bigger HDD to store them all comfortably.
Graphics Card:
Graphics card are also known as Video Cards although their proper name is a GAC (Graphics Accelarator Card). They simply generate images that are displayed on the monitor. Graphics designers requier quite good GAC as they require the best detail they can get from their screen and they also require fast rendering to be able to tone up their work efficiently.
Processor:
Processors, or CPU (Central Processing Unit), is a circuit that is built to execute computer programs by executing a sequence of instructions called a program. CPUs use four steps; fetch, decode, execute, writeback.
- Fetch - Retrieving the instruction from program memory. To find the location of the instruction from the program memory they use a Program Counter (PC), and this stores a number that identifies the current position in program. Once the instruction is fetched the PC reads the instructions in terms of memory units.
- Decode -The processor breaks up the instruction into parts with significance to other parts of the CPU.
- Execute - Portions of the CPU are connected together to allow them to perform the operations needed.
RAM:
A type of computer memory. Much more expensive than HD memory and the amount determines how well/fast your computer can handle the open programs on your computer. Having a larger RAM will help to increase your computers performance speed, and allow you to edit images easier and have less chance of freezing.
