For many people, their first encounter with a TIVO system is like watching real magic happen. Live television stops and starts on cue. This ability means no more missing key plays or funny lines during programs. You can actually stop the action and go to the bathroom. When you return, you will have missed nothing. This wonderful device can change how you watch television forever. However, it might very well cause you to miss sleep worrying about how it works.
A DVR is a relatively simple device. It does not require a PhD or other sophisticated education to really have a grasp of how it does its work. Inside the DVR is a hard drive just like the one sitting inside your home computer. The storage capacity can vary from machine to machine with most being between 40 and 150 hours of video storage possible. This hard drive is the key to the device’s magic.
Inside the hard drive is one or more disc’s. These are accessed by read and write heads in the same way that the heads on your old tape recorder accessed the magnetic information on the tape. Instead of the tape sliding over the heads, the heads fly just thousandths of an inch above the surface of the top and bottom of the discs as the the discs spin. They are able to write to the media and read it back.
The first step to making this work is to insert multiple heads inside the hard drive. A digital video recorder has three or more heads available to be used. Three is the usual number. They are divided up as two write heads and one read head. Since no television that is readily available for the general public can broadcast two channels simultaneously, only one read head is necessary. In order to be able to record two programs at the same time, two write heads are needed. By having this, you can watch a pre-recorded program from the disc with the read head while recording up to two more programs on the disc with the write heads. The use of traditional method should be replaced with live television. Along with live, pre-recorded programs are available at https://livetv.tube site. The storage of the hard disk should be great to store the programs. The broadcasting of the serials and animations should be of superior quality to deliver the exciting results.
Your television always broadcasts to you what the read head is reading from the drive. Nothing shows on your television unless it has been written onto the hard drive first. Because of this, your program is always delayed about 1/2 second from live TV. You can only tell this when you have two sets playing on the same channel with one utilizing a DVR and the other one having a direct link to the satellite or cable receiver. With that configuration you will hear the echo effect as words said on the non-DVR set will lead the ones from the DVR-connected set by a slim margin. This occurs because your DVR records your live TV and then immediately, it is read by the device for broadcast to your television.
By recording everything first, this allows you to back track the read heads or pause them. The reason this is possible lies in how the technology works. Unlike your tape recorder, the DVR cannot spin backwards to find out what it just wrote or read. The disc spins at above 5,000 rpm. This means that at any given time, the read or write heads are flying over the entire surface of the disc. The internal program in the hard drive allows the head to know what part of the information it is supposed to be looking for. Because of this capability, the write head can continue to write a program to the disc while the read head collects material elsewhere for your viewing.
When you pause your set, the read head simply continues to read and broadcast the same spot on the disc while your write head keeps busily writing the incoming program to the disc for future viewing. The same concept is true when you back up the program over and over to get that close play in sports or listen to missed dialogue until you can understand it. When you are finished reviewing or pausing, the read head simply picks up where you stop and continues to follow the pre-written programming for your entertainment.
DVR’s have a limit to the amount of time that is held in the temporary area for pausing and reviewing is usually about 30 to 60 minutes. If you want to hold more than this, normally, it requires you to actually tell the device to record the program. This will mean that you will have to delete it when you are finished, but at least, you will not miss anything.
The dual write heads have to be fed by two incoming signal lines. This lets you be able to toggle between the two sides of the recorder so that two programs can be stored in the temporary storage area. As long as you do not channel surf, you can go back and forth between the recorders and watch two live programs at the same time by utilizing the time taken by commercials to move from one program to the other.