Intergrated engineering physics by Dr. amal chakraborty

This is the book you need in 2nd sem of engineering(all stream)link is down below... click on download 

Click here

Sayan Chatterjee from naktala

this is me the administrator of this blog and as a a scientist I would like to acknowledge  you about me like I am a computer science engineer and I am a writer too, a violence thriller writer.

SATA & PATA

When You have to know about hard disks the first thing you need to know is their interface and SATA & PATA is two different interfaces of hard disks with motherboard, PATA is the older interface and slower connection than SATA.

   PATA or Parallel ATA is designed by Western Digital on 1986, it’s a 40 pin interface and also called IDE. PATA runs on speed maximum 133 Mb/s, in 1986 when PATA first came into market it used to run at 16Mb/s speed and there was later 33, 66, 100, 133 Mb/s speed. PATA is not hot pluggable under any circumstances and PATA works on Master and Slave technology so in PATA one hard drive works like a master and controls other drives like DVD drive, You can’t make RAID in PATA.

SATA or serial ATA or serial advanced technology attachment was first in market on 2003, although when SATA first came into market could not impress at all, because SATA 1.0 (1.5GB/s) has original speed of 150Mb/s slightly faster than the latest PATA connection and hot pluggable but SATA was costlier that time. But after release of SATA 2.0(3Gb/s) on April 2004 of original speed 300Mb/s SATA started to take market share aggressively because SATA was faster , simple and less space consuming, SATA was only 7 pin connector, and after SATA 3.0 (6Gb/s) original speed of 600Mb/s SATA took all market share on 2009.

e SATA

Most of the people don’t know that there is SATA 3.1(released on 2011) & 3.2 (released on 2013), which has theoretical 16Gb/s speed and actual almost 2Gb/s speed, SATA 3.2 is called SATA express, it works like a pci bus that’s why it’s that faster, And don’t confuse  this with e SATA, e SATA is external SATA which can be used like usb for hot pluggable storage device.

SATA power

POWER

PATA power

PATA used to use a 4 pin simple MOLEX power connector but SATA uses a 15 pin SATA power connector.

Why you should must learn C programming language?

Well, can you learn any simple language without learning your mother tongue?  No… just like that you cannot properly learn any programming language without learning C.

  Are you thinking that C is really very backdated and not being used anywhere!.  embedded C is used in most of your smart home appliances, are you astonished?  Don’t be, because there is no programming language which beats C in compiling and executing speed, and you don’t need a costly or powerful chip in embedded C, simple atmega 8  will do your job which cost almost 3 US$, seems very cheap right?

  So, C is still not completely thrown out of the market and C is very easy to learn also, one educated 15 years old boy can learn C in only 7 days… can you believe?

Yes, everything of C can be learn t in only 7 days if you really concentrate.C was invented for building UNIX OS by Denis Ritchie on 1972!

   What do you think , why C ruled in IT industry for 25 and more years alone?(still in use)

Execution speed , easy to learn or compiler availability what is it… comment it below and let me know what you think about it?.. is learning C waste of time or very much needed?

Happy Programming.

   

What hard disk you should buy this year?

   Well, I will just let you know some thing about hard disk history first, even in 1984 the original Macintosh had no hard disk at all, program and data both used to be stored in floppy disks and later hard disks came as additional feature, they were very noisy and slow to transfer data, and failing rate was too high, Take a look at a  Maxtor 10 gb fat noisy hard disk from 1990

So, let’s back to the original topic , which hard disk you should buy this year? Of course you want a ssd right ? ( see my ssd or hdd article to be sure ) and are you thinking to buy a SATA interfaced ssd? Why??????   SATA has maximum speed of 16 Gb/s , actual speed 1969 Mb/s . why to put a semiconductor based ssd on slower SATA port? Do you know USB 3.1 is even faster than SATA? \

   Then what should you do?

Go for a pci-E based or pci enhaced based ssd like    go to this amazon link

Well, that will be a little costly but just think about it …. You were using a train engine to pull a bicycle. ssd is fast but not fully fast in SATA,

So, you probably should buy a pci-E based ssd for your primary hard disk to enjoy full performance. Apple use this pci-E based hard disk in all of their Mac books.

Happy and fast data transferring and Happy Durga Puja to all.

Lcd and Led

  Ok, everybody knows that lcd is liquid crystal display and led is light emitting diode but did you know that led displays are actually led backlight lcd ?... or lcd has got ccfl backlight? No? Then read the entire article.

   So, there is not much difference in lcd and led, only the backlighting system is different and that’s why led displays consume that less power compared to traditional lcd displays, well lcd displays used to contain low quality human eye hurting polarized glass and led displays use better polarized glass, but that’s minor.

   There are lots of types, like TN panel, IPS panel, and etc.

    TN panel is very basic and cheap and colour production is not great in TN panel but in IPS panel the colour production and resolution is really very great and it’s  really good for human eyes, and there are different types of led also, like high brightness led and low brightness led, their brightness is measured by nits unit

  Next time when you are buying a display then check for the panel type and viewing angle and nits and power consumption and contrast ratio.

Happy monitoring.

Cache memory explained

    Cache memory is not that common word for regular people, now some people know what a RAM or CPU is or motherboard is but cache memory? ... nuh!

That’s why I am here to explain cache memory, even if you know what a cache is then you probably don’t know it deeply or very well, or know it all wrong so, let’s start.

     Now don’t confuse with HDD cache and CPU cache , today we will talk about both of them but by saying cache memory we primarily understand CPU  cache,

Before 1980 there was no cache in computers.

CPU cache remain in between the RAM and CPU because RAM is way slower than CPU just see… a 3.7 GHz CPU has to work with a DDR3 1800 MHz RAM, the speed the not matching right?... So, t5he CPU will complete the work faster and the RAM will lag, to solve this bottleneck computer scientists introduced a much faster and costly memory called cache and to reduce the price the used the cache between RAM and CPU to synchronize the speed. The more your CPU has Cache the faster it can transfer data, don’t know what L1, L2, and L3 cache is?

 I am here to tell you…. 

L1 cache is costlier than L2 cache and faster also so L1 is smaller in size than L2, just the way CPU is transferring data from RAM through cache CPU also transfer data from L3 cache through faster and smaller L1 cache.

Time to talk about HDD cache

HDD cache is just situated in hard disk to make the hard disk more faster now when the cpu calls some data from hard disk the data transfers through RAM and hence HDD is much slower than RAM here data also bottlenecks, to solve this problem there is a Cache in HDD which is in between all other component of computer and the HDD. HDD cache is less costly than CPU cache and now-a-days HDD cache is normally be 8mb to 128mb and SSD contains up to 1 GB of cache.