FILE TRANSFER TIME CALCULATOR FULL

And it assumes that calculating the checksum takes about no time flat.It also ignores that the data might already be present in the drives cache.(4KiB can be 8 reads of 'Header|data|checksum|gap' or a single read. File Transfer Time Calculator Try our transfer speed calculator to see how much time we can save for you Check the Speed Calculator Choose a scenario. (which is a matter of rotation speed, length of data to be read, length of the checksum data and inter sector gaps. But there is no information on how fast the data is read from the platter.the drive needs to read the data before it can transmit it, this will make it slightly slower.Or 0.488281 ms, which is your latest 0.05 ms.80 MiB in one second, or 80*1024 KiB one one second, or 4 * 20 * 1024 KiB/second.Reading from the drive is usually much quicker than passing it, so I am going to focus on the slower part: It will still need to read it and pass with to the host. So half a rotation should will take half that time, 1/ 240 th of a second.Īll of this is the time until the drive can start reading the data. Or a single rotation takes 1/ 120 th of a second.7200 rotation per minute (aka 7200 RPM).

FILE TRANSFER TIME CALCULATOR FULL

To get the time for a full drive rotation on a 7200 RPM drive: In the average case the drive needs to wait half a rotation.In the best case the data sector has just arrived.In the worst case the data just passed an it has to wait a full rotation.We are given that it is a 7200 RPM drive. Once the head is over the right track it needs to wait for the right sector to pass beneath the R/W head. The 5 ms seek time is the time for the harddisk to move its head to the right track (and to select the right head, something which also takes time but which your prof. Solid-State Drive: Seek Time + Transfer Time

Thus, in general, the total access time to read a single sector for a drive is (neglecting software): Rotational/Hard Drive: Seek Time + Rotational Latency + Transfer Time Note that for solid-state drives, while there is no rotational latency to take into account, there certainly still is a measurable seek time (to actually address the contents of the sectors in the flash memory) and transfer time (largely limited by the bus being used to transfer the data itself, e.g. Thus, to transfer one block to the computer, we must wait the equivalent Seek Time + Rotational Latency + Transfer Time: 5 ms + 4.166 ms + 0.05 ms = 9.216 ms At 7200 RPM, in the worst case, we have to wait 1 full revolution, but on average we have to wait a half-revolution - or 4.166ms (7200 RPM = 120 rev/sec = 8.333ms/rev). This equates to 0.05 ms to transfer a block, explaining the last term in the equation.įinally, in addition to seek time (time to move the drive head to the track), there is also the rotational latency of the disk itself to deal with. Here, we will round off to 20,000 blocks/second, since this appears to be what your professor did. The disk in question has a transfer rate of 80 MiB/s, or 81920 kiB/s, or 20480 blocks/s.

File transfer time calculator