History of Technology 20

History of Technology 20

Hard Disk

08sHistory of Technology 20.Long-term memory is the part where they are stored ideas and even if you do not need them right away, you should know (eg number of shoes, no. Of phone etc). In computers, this kind of “memory” is called hard disk. The hard drive stores all user installed programs, and numerous file formats, multimedia (video, audio), documents, etc.

Hard disks are some “boxes” sealed, and comes back with a circuit with various electrical components. A hard drive connects to the motherboard of the computer through a communication interface. Hard drives running on magnetism.


The principle is simple. Some materials become magnetized under the influence of a magnetic field. Once magnetized material, remember that magnetic field.

The key of memory and magnetism is permanent. Magnetic fields have a great capacity to be static and semi-permanent. Do not move and do not change by themselves. Electricity used in electronic circuits is the opposite. We continuously search for ways to electricity dissipates, being constantly on the move. The difference is fundamental. Magnetic fields are made of atomuri spins locked into place. Electrical charge is carried by mobile particles – mostly electrons – which refuses to stand still.

Given the right amount and the right strength, can spin magnetic sites upset, and can change their orientation. Since magnetic fields may change and are not permanent magnetism is suitable for data storage.

A magnetic force that change is another magnetic field. Despite the different behavior in electronics and storage systems, magnetism and electricity are manifestations of the same elemental forces. Both are an electromagnetic phenomenon.

virtual memory

Right from the beginning computers to plan an exchange between computer memory and storage devices hardware. Memory was expensive that even the largest corporations could not afford to have as much as needed. Engineers have tried so memory prices fall, “faking it”, making believe that computers have more memory than they. With numerous sketches and games to bits, they used a certain percentage of storage space (on your hard drive) memory, called virtual memory because there physically.

Microprocessors can not use the storage space (HDD) for working with data. Even if they could, would drop drastically system performance due to too high access time, hundreds of times higher than for ROM type memory. For better performance, the data blocks are exchanged between ROM and virtual memory, the first being loaded only data blocks required for running the software used at that time.


Computers can connect to networks, they can be attached peripherals, printers, scanners, cameras, etc. Because of the connection capabilities and can connect any hardware through the gates of entry / exit. With computer modem or network card can connect via Internet to any other computer in the world.

Computers communicate with peripherals located in the housing ineriorul bus. The capabilities of a computer can be increased by attaching the components are inserted into slots on the motherboard. Depending on the design of your computer, it may contain a different number of slots where you can install a video card (for input – TV tuner – or output – to connect to a TV), audio, network card, modem, and so on


Interfaces provide a communication channel that allows the computer to exchange information with many types of devices, including storage devices. Interface “translate” the computer signals into a form suitable for travel outside the system (motherboard). These interfaces are listed and ATA (commonly called IDE) or SCSI, SATA, etc., used to connect any hard drives or optical drives.