Some more terms about hard discs

Welcome back friends! I hope you will be enjoying the posts. Today we will discuss some more terms relating to hard discs.
SATA: (Serial Advanced Technology Attachment) Like IDE cable it is also used to connect hard discs and CD/DVD Drives to the port on the motherboard. It is serially communicating interface that means data travel on it in the serial mode i.e one after another. works faster than the conventional parallel cables and is also longer than the IDE cables but less in width. It may be up to 1.5 meters long. A SATA cable may support speed of 150 to 300MBps (Mega Bytes per second).
SCSI: (Small Computer Sytem Interface) :It is an advanced version of IDE/ATA interfaces. It is used to optimize data flow and is system level bus with controllers on each SCSI device.
RPM: (Rotations per minute) The speed of the platters in the hard drive is measured in rpm. The platters are mounted on a spindle. Faster the spped better the hard drive as it effects over all speed of a computer. Most common speed of the hard drives these days is 7200 rpm where as for a laptop it is 4200 rpm.
Platters:These are the flat round discs usually made of very thin soft plastic and coated with magnetic material. These are used to actually write/record and read the data with the help of magnetic heads just like the tape recorders earlier used to record and play the songs and music.
In the next post we will discuss some more aspects about the hard discs. Enjoy reading till then.

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Know your hardware (Memories)

Hello friends!
Welcome back! In our earlier blog we were reading about hard disk. Do you know where our data resides in a computer? Most of our data is stored in hard disk which is a secondary type of memory. RAM and ROM are the types of primary memory. Primary memory is an integral part of our CPU, whereas Secondary memory i.e hard disk, floppies, compact disks (CDs), digital versatile disks (DVDs), USB Drives are external.
The necessary instructions/programs which are required to initially start/run a computer resides in the ROM. These programs (set of instructions/commands) are stored in the Read Only Memory at the time of their manufacturing by its manufacturers, so it is also called Firmware. Its variations are 1.PROM Programmable ROM, that can be slightly programmed/changed by special device called ROM Programmer. Once programmed, then contents can not be changed 2. EPROM Erasable Programmable ROM i.e Its contents can be erased if required by a difficult process using ultra violet light rays, 3. EEPROM Electrically Erasable Programmable ROM, its contents can easily be changed by means of electric pulses.
RAM another type of primary/main memory is used by the processor of the computer as a scratch pad. The data remains in RAM until it is not saved. Once saved, data goes into Hard Disk of the computer. RAM is temporary memory. It is also called volatile memory because it retains data as longer as voltages are available to it. Once the computer is off it forgets every thing.The following are the variations of RAM.
RAM: Random Access Memory ( so called because processor can pick up the required data randomly which is necessary for maintaining the speed of computer or speedy execution of commands/instructions) Some times RAM is also called Read and Write Memory as unlike ROM data can both read and write from and on the RAM easily.
SRAM: Static RAM, requires constant refreshing by the electrical pulses at a much higher rates to retain data stored in it.
DRAM: Dynamic RAM, requires refreshing but less frequently, some more speedy than SRAM
SDRAM : Synchronous Dynamic RAM , this is the fastest of all types of RAMs
RAM and ROM are both types of memories are fabricated on a special type of semiconductor i.e Silicon chip. So also called Semiconductor memories.
In our next post we will know more about the memories. Enjoy reading till then. Yes do not forget to comment and let me know what you want to know about. Check out our website about the computers http://www.desirachh.in I have changed its looks and themes. Let me know whether you liked or some more suggestions may also be emailed to me: asiraj_67@operamail.com

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Video: Analogue or Digital

Hello Friends!
Welcome back. Let us today compare two types of videos i.e. Analogue and Digital. We will see which is better.
It is very difficult for our eyes to differentiate between analogue and digital video. But digital video is always preferred because of the ease with which it can be created, edited, transmitted, stored or received.
It is very easy to edit a digital video or to store it as digital format offers a great advantage over anlogue format. We have to choose a suitable special software and we can edit our digital videos. We can store hundreds of movies, or movie clips, on hard drivesand other storage media like CDs,DVDs,USB Pen drives and also on Memory cards of our mobile phones. We can make copies of our personal videos and share them with our friends or family members staying far on the Internet through emails. with the help of computers in our lives ,doing all this has become a kid's play.

On the other hand with analogue videos, we need to store each video on a separate video cassette. For making copies of that cassette will require two video casstte recorder (VCRs). One for playing back the cassette, and second for recording the video in real time on to another cassette. Also this is a very difficult and time consuming task.
The equipment required for analgue videos is costly, where as we can easily buy digital equipment like CD Players, DVD ROMs/Writers, Web/Digital Cameras very easily.
Quality of digital video is much better than analogue. You can check and also using while viewing digital channels on Satellite TV
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Video

Hello friends!

Welcome back. We hear the word video many times in our day to day life. We use it and enjoy it. Have you ever thought how these video are created and how it is possible to move a picture? Let us try to understand basics of video.
You all have seen photos, these are called still images. If these are brought in front of your eyes at very fast rate one after one with some mechanism it gives illusion of movement i.e. we will see these still images moving. These still images are called frames in technical language & rate at which these are shown is called video frame rate. Human eye is capable of seeing less than 25 different images per second, so video having rate more than 25 frame per sec. will be experienced as smoothly moving as we saw in movies. If a video displays less than the speed it will appears to be jerky i.e. interrupted as you experience when seeing a scratched and old CD.
There are three standards of video prevailing in world. These are 1. PAL (Phase Alternation Line) with 25 fps (frames per second) for Analog Video 2. NTSC (National Television System Committee) with 30 fps. PAL video format is widely used all over the world for TV signals. In the USA NTSC is being used. Third standard is Secam and it is less used for TV Signals

. You might have seen these words while changing setting of your Television set or VCD/DVD players.

The video is categorised in two types i.e. analogue and digital. Analog Video transmits and stores video data in continuous wave form (also called sinosuidal wave i.e.that can have any value at any instant) of red , blue and green, (RGB) colours. These colours are called primary colours as any colour can be obtained from the combination of these colours. To display changing images in TV , the signal is varied using different frequencies of each colour's wave. Analog video data is more prone to distortion.
In digital video analog signal is converted into two binary digits (0,1) as modern computerized devices can understand binary only, stored & displayed on screen repeatedly at very fast rate i.e. refresh rate. In this way we can say that digital video is the computer's understanding of analog video. However these days some application like games can be developed using digits directly i.e. analog signals are not required.

In our next post we will try to compare both these types of videos. Enjoy happy reading and viewing good videos till then. Don't forget to comment how you feel about this post. If you liked it, email to your friends also.

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