Part 1
Before starting with the computer description, it is useful to become proficient with the data size terminology, which will often be used.
Computers have a very elementary way to store data: they can remember only 0 or 1. A value of 0 or 1 is called bit and all computer data are stored as sequences of bits. A sequence of 8 bits is called a byte, which is a quantity large enough to store usually a letter or a digit (even though sometimes 2 bytes are necessary). Modern computers are able to deal with enormous quantity of bytes, forcing us to introduce other quantities:
1. Kilobyte (KB), approximately 1,000 bytes,
2. Megabyte (MB), approximately 1,000 KB or one million bytes,
3. Gigabyte (GB), approximately 1,000 MB or one billion bytes,
4. Terabyte (TB), approximately 1,000 GB or one trillion bytes.
Over the last 40 years, computer hardware has been continuously improving its performances with an exponential growth. This growth is summarized by the famous Moore’s law which says that the number of transistors in a processor doubles every 18 months. This law can be extended to almost every aspect of hardware and we may say that the performance (be it speed or capacity) of hardware doubles every 18 months, thus leading to a general exponential growth. Unfortunately software’s performance does not increase with the same rate.
The computer uses several devices to permanently store and move data, which vary a lot in terms of capability, cost, speed and portability. The most used is the internal hard disk, which usually is inside the computer box and cannot be moved. Its size currently ranges from 1 to 2 TB. On the other hand, an external hard disk is outside the computer, has the same size and obviously can be moved. Its only disadvantage is being slightly slower. SSD Solid State Drives are starting to invade the market and will soon replace traditional hard disks. They are not disks at all, but very large memory cards shaped like a hard disks which can entirely replace the internal hard disk. Their main advantages are that not having moving parts (they do not rotate at high speed like hard disks) are more robust and that in most situations they are faster than hard disks (up to 10 times faster). Their disadvantage is the limited size which currently is 500 GB and their high price
CD, DVD and Blu-ray are an alternative way to store data. They contain about 700 MB, 4 GB and 25 GB, respectively. They required an appropriate reader to be read, which is available on many computers, and an appropriate writer device to be written, which is available only on some computers. This technology is, however, rapidly fading, as disks are much larger and easier to damage compared to USB pen drivers or memory cards. Memory stick or USB pen drive is the most used way to temporary store and move data. Its size is now up to 128 GB, however its reliability is not perfect, therefore it is used mostly to move data. Another common way to store and move data is through a memory card, used by external devices such as photo cameras or to expand mobile phones’ memory.
Find Original Video here: https://www.youtube.com/watch?v=HvqmQAQLBxk
Before starting with the computer description, it is useful to become proficient with the data size terminology, which will often be used.
Computers have a very elementary way to store data: they can remember only 0 or 1. A value of 0 or 1 is called bit and all computer data are stored as sequences of bits. A sequence of 8 bits is called a byte, which is a quantity large enough to store usually a letter or a digit (even though sometimes 2 bytes are necessary). Modern computers are able to deal with enormous quantity of bytes, forcing us to introduce other quantities:
1. Kilobyte (KB), approximately 1,000 bytes,
2. Megabyte (MB), approximately 1,000 KB or one million bytes,
3. Gigabyte (GB), approximately 1,000 MB or one billion bytes,
4. Terabyte (TB), approximately 1,000 GB or one trillion bytes.
Over the last 40 years, computer hardware has been continuously improving its performances with an exponential growth. This growth is summarized by the famous Moore’s law which says that the number of transistors in a processor doubles every 18 months. This law can be extended to almost every aspect of hardware and we may say that the performance (be it speed or capacity) of hardware doubles every 18 months, thus leading to a general exponential growth. Unfortunately software’s performance does not increase with the same rate.
The computer uses several devices to permanently store and move data, which vary a lot in terms of capability, cost, speed and portability. The most used is the internal hard disk, which usually is inside the computer box and cannot be moved. Its size currently ranges from 1 to 2 TB. On the other hand, an external hard disk is outside the computer, has the same size and obviously can be moved. Its only disadvantage is being slightly slower. SSD Solid State Drives are starting to invade the market and will soon replace traditional hard disks. They are not disks at all, but very large memory cards shaped like a hard disks which can entirely replace the internal hard disk. Their main advantages are that not having moving parts (they do not rotate at high speed like hard disks) are more robust and that in most situations they are faster than hard disks (up to 10 times faster). Their disadvantage is the limited size which currently is 500 GB and their high price
CD, DVD and Blu-ray are an alternative way to store data. They contain about 700 MB, 4 GB and 25 GB, respectively. They required an appropriate reader to be read, which is available on many computers, and an appropriate writer device to be written, which is available only on some computers. This technology is, however, rapidly fading, as disks are much larger and easier to damage compared to USB pen drivers or memory cards. Memory stick or USB pen drive is the most used way to temporary store and move data. Its size is now up to 128 GB, however its reliability is not perfect, therefore it is used mostly to move data. Another common way to store and move data is through a memory card, used by external devices such as photo cameras or to expand mobile phones’ memory.
Find Original Video here: https://www.youtube.com/watch?v=HvqmQAQLBxk
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