Digital Electronics RAM is not same as Computer Organization RAM.OmG!

We were having a Digital Electronics hardware practical class. One of my friend was given the task to store and retrieve data from the 7489 IC, a 16×4 = 64-bit ram chip. The circuit assembly was very easy and was done very fast. Now just to enter data and take out and check if they are the same with the stored data. Practical complete. But the practical class ended other people finished their assigned works. But the friend disassembled the circuit, and reassembled it and double checked the connections. I asked “what’s the problem” . Answer “I cannot get the proper output, 0s are stored okay, but the 1s are not. Whatever I store in the RAM I get 1111 as output” (The output of 7489 is inverted). Some more time passed. At last I suddenly noticed he was switching the power on taking some readings and putting the power off.
In the practical lab, before changing any wire connection we shut the power down for safety. But when I had a close look of what he was actually doing is described as follows: He fed some data in the first byte of the RAM chip, shut the power change the wire connections to feed data in the second byte, turn on the power, then turn off the power, change the wire connection for new set of data in the next byte, turn on the power and so on. And when he was finished feeding all 64bits, tried reading the data.
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HardDisk platter moves!

This one is from the school days. We had a compulsory basic computer classes in class 8. The day the teacher started to describe how a computer hard disk work, under input/output chapter. He told there were some platters, ie. disks inside the hard disk box, and they rotate in very high-speed, and as the head positions itself in the proper location over the platter and flies on it the data is read. Everything was pretty fine till now until the next thing was told. He said, “when one platter is full with data it moves down the stack of the platter to the bottom, and the next disk is used”. “Woah!, OOohh!, Ure Sala!” these were some of the reactions from the students. He continued, “and that’s why hard disk drives are slow, it needs to switch platters when some data is needed is not in the current platter”. Some body protested using his common sense, “where is the space for the platter to move down the stack?”. Answer was “it might seem there is not enough space but it actually is designed like that.”

Next day another teacher came to class, everybody told him about this, his reactions were: “Did he say so? Really? ….. He has gone mad. Ok let it go ..” , and he described the real mechanism of the hard disk.

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Latest Myth: Fedora Cannot run Shell Script


A lot of people running around asking for RedHat Linux, suddenly, and most of them at last getting pointed to me and getting disappointed. When asked why RedHat, and why not any one among the hundreds of other distros, I came to know a very important information: “Shell programming cannot be done in fedora”. It was very difficult to understand how this idea spread virally around the 3rd year honours Asutosh College students (a lot of them). The strangest part is even a shell program is run in front of the mass, they refuse to believe that Fedora actually can run shell script. It feels like someone going down to Sachin Tendulkar and telling “Hey man, you know nothing of cricket”.

Whatever it be it is better to get out of this myth and face the cruel reality : “Fedora CAN run shell programs” . Before comments to this post starts raining asking why, let me tell what I know and support my statement.

To run shell scripts you need basically the below three components:

  1. An OS kernel
  2. A shell
  3. The set of commands which will be used in the script

Now, in GNU+Linux systems we have the Linux kernel, The bash shell (some may have others as well), and the standard set of commands are the coreutilities. There are some more packages which contains some commands (programs) which are used.
Each of the above components are very basic and includes in all the GNU+Linux operating systems. Even an OS of size below 10MB can contain the components, which any one with proper knowledge can make for herself. Even before booting the Fedora or any GNU+Linux OS, the initial ramdisk image the initrd runs a long shell script, which configures the system and helps fedora or any GNU+Linux OS to boot.

Conclusion: Fedora can run shell scripts (Sachin can play cricket), provided the programmer knows shell scripting. (provided the bat is not a table tennis bat).

Pause and Break the Key

Yesterday in college I found an IBM keyboard with a broken Pause/Break key. Now why is this particular key broken, when It is rarely used? Almost instantly I realized, that the answer was written on the key, a previous user might have just followed what was written on the key.

Copying by Writing is Copyright making FOSS illegal !!

A new teacher was taking her first class. She was skimming through the points of Software Engineering. When discussing about software cost she told that Software is costly. One student suggested and told that, what about Free Software. She corrected him by telling that the software we use are Pirated and distributed in “Copywrited” discs and illegal , so we do not have to pay for these, and thus it is Free. Students got confused. Another guy asked , if the software is in a “Copyrighted” disc then why it is illegal. Then she tried to describe that what is original software and a licence is provided with it. After some more confusion a student ultimately asked — “What is Copyright” . The answer from the teacher was something like this when translated: “After a legal original software copy is bought, we copy it and write it in a CD , and so we call that a “Copywrited” software which is distributed for “Free” .”

Note: When reading please note the “Copywrite” and “Copyright” spelling
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Playlist Compression Joke

One fine day I got a phone call from my friend. He told me a good method to save memory space of his mp3 player which he worked out. The process was something like this: Create a playlist with all songs, remove all songs, and keep only the playlist which consume minute memory.
And oh, the next day he had to come to my place to get the songs back (the last step of the process I guess).
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