Why Is a Ssd Page 4kb?

Why is a SSD page 4KB?

HDD stands for Hard Disk Drive while SSD stands for Solid-State Drive. Both are used to store data, but the way of storing data is very different. HDD [img source. Hard disk drive platter | Wikiwand] You see HDDs have a spinning disk called platter made up of either aluminium or a very strong piece of glass. T are very smooth and shiny. [img source. Hard disk drive platter | Wikiwand] The above platter is made up of glass and it’s broken just to give you an idea of what glass platters look like. The platter stores the data into chunks of memory. Generally, the big and bulky desktop HDD (3.5″) rotates at 7600+ RPM and the platter is made up of aluminium. The laptop ones (2.5″) are mostly 5600 RPM and the platter is made up of a strong glass, which takes a lot of effort to break, but when you break, it breaks with razor sharp pieces. The RPM is a major factor determining the read/write speed. The more the RPM more the read/write speed you get. Now as the platter spins, there’s one arm called actuator which moves like the arm in the vinyl record (File.Vinyl record close up.jpg) and reads/writes data from and to the platter. In the head of the arm, there’s a very tiny little electromagnet which looks like this. That reads and writes the data to the spinning platter. There’s a visible circuit board in the HDD that controls the speed of the rotation and also controls the arm and helps to read and write data. That’s it, this is how generally an HDD works internally, and the performance depends on the file system and other factors like block size, alignment etc. SSD [img source. Solid-state drive - Wikipedia, File.HGST SN150 NVMe flash SSD, PCI-E add-in card (rear view).jpg] Unlike HDD, as the name suggests SSD have no moving parts. T are just solid and have no platter kind of thing. The data is stored in a chip rather than on a rotating platter! The chips are called NAND chips. That said, the cheap SSD are your phone’s memory card and your thumbdrive. T are also solid and have no moving parts in them. When you write a data to them each bit of data is stored in a tiny circuit known as a memory cell. There are billions of cells and each one is made up of one or more transistor(s). The performance depends on the file system, block size, alignment etc. other factors. Comparision Power Efficiency. Because physically moving a platter uses more electricity than solid-state drives, that means HDD are not very power efficient. A general 2.5″ HDD can use 2.5 - 10 watts of power while SSD generally use less than a watt! Here’s a look at my 1 TB Toshiba HDD running with a HDD case with USB 2.0. I don’t know how accurate the USB power meter is. But you can see it uses 2.5 watts of power while I was copying a 1.5 GiB file to the HDD. Do note that the power provided from my laptop’s USB 2.0 is limited to 500 mA only. But the result is consistent with USB 3.0 as well. The larger HDDs (3.5 inch) consumes more power. The power goes up when the HDD has more RPM. Here’s another example with another HDD, external HDD this time. This is not throttled by USB 2.0’s 500 mA output, rather it’s connected to USB 3.0 while a big file is written. The SSD uses < 1 watt of power shown by this meter which isn’t added in this answer yet. Also, due to friction, HDD tend to generate more noise and gets a little bit hotter when you run them for a long time! Performance. In an HDD the platter spins up while the arm reads/writes the data. In contrast, SSD is solid, it reads and write data from and to the solid chips. Because physically moving the platter takes a lot of work to do, and taking into account the arm need to position itself correctly and has to wait for the right position of the platter to arrive makes an HDDs’ both random and sequential read/write way slower than an SSD. [Note that most of the SSD (generally not the cheapest ones) and HDD in the market have DRAM so that when you copy a small file, it’s written to the faster DRAM rather than on the platter / memory cells of the SSD. This increases speed, but sometimes that can cause data loss if you unplug the device even when your copy is done to the storage medium. So always make sure to unmount and eject the storage medium even after your system notifies that the copy is done.] Also do note that filling up an HDD makes it slower because in HDD the platter spins. So the actuator has to wait for the right moment of the disks to fetch or write the data. So the sequential read can get very very slower when your HDD fills up in contrasts to SSD which almost works like a magic even when it’s mostly non-empty. Personally speaking, my computer running Arch Linux on an HDD, boots up the computer in 1 minute and 15 seconds. I replaced the HDD with an SSD, and the same OS boots at 5 - 10 seconds on my computer and 15 seconds for my laptop. The app launches are way faster. Say on HDD opening blender takes 10 seconds, on SSD, it’s just a second. The read speed of my WD Green SSD looks kind of like this. For my HDD it’s like this. [The software I used for benchmarking is gnome-disk-utility (udisks 2.8.4, built against udisks 2.8.2)] You see an HDD is very slow! But also note that it’s sequential read. For random reads, it’s even slower than your memory card! Reliability. Both SSD and HDD are quite reliable nowadays, you don’t have to worry too much about that. But generally speaking, SSD have shorter life span. You see when you write a data to it, the data is stored into memory cells. Next time when you delete the data, the data is not get deleted. You can restore them anytime you want if it’s not overwritten. And after the deletion then you write some data (say a music) on your SSD again, it stores the data some other memory cells store it because it takes significantly longer to overwrite the data you deleted. This is generally managed by algorithm like TRIM. There are other ways to handle the efficiency (e.g, over provisioning). On a GNU/Linux system TRIM can done with. That’s why you shouldn’t fill your SSD. Generally speaking, that’s the reason behind manufacturing 120 GB SSD rather than 128 (2 ^ 7) GB SSD. A part of the 8 GB contains the firmware, TRIM algorithm, garbage collection, while the most part of the 8 GB is unallocated so that you don’t have to worry about filling it up and destroying it. The same reason goes for high capacity SSD. You will not see as many 256 (2 ^ 8) GB SSD as there are 240 GB SSD nowadays. For SSDs the manufacturer specifies how much terabyte you can write before killing it. When you go beyond that level will see bad blocks appearing, and your SSD stars dying. If your SSD has a S.M.A.R.T. attribute called TBW(TeraBytes Written), you can check for how much terabytes is actually written on your SSD. This is the reason people say not to create a swap partition on an SSD because pages from RAM will be copied to it depending on the swapiness and the available RAM on your system. In April 2019, I got a fake HP SSD from my local dealer. [In the fake SSD when you write data, you will see the reallocated sector count increases, it will die the next month of buying when you write 70 GiB data to it. Be careful while purchasing SSD]. That’s for the pricey SSDs! For memory cards, the expected life is even shorter, and you can easily kill one flashdrive by installing OS on it, and using the OS for 2 - 3 months (I killed 3 of my SanDisk thumbdrives this way 😞 ). HDDs generally can handle heavy IO, and you can write data without worrying much. There’s no such TRIM or over provisioning kind of thing available for an HDD. Throughout an HDD’s life, it can handle way more write than an SSD. But HDDs are prone to get affected by vibration. SSDs can’t be damaged badly with such vibrations. It’s a good idea not to shake an HDD when it’s running, because when it runs, the actuator levitates over the disk and touches it most of the time. Shaking or vibrating it will cause the actuator to bang the platter, and ultimately put some invisible scratch on it, which will lead to bad sectors. HDD are more prone to get damaged with heat. Nevertheless, it’s not a good idea to heat both HDDs and SSDs. But in general, HDDs, when get overheated (generally over 70 degrees) can cause serious data loss because the platter can loose the magnetic states. Overheating can also cause bad sectors. A very low temperature can also lead an HDD to stop working unexpectedly. Do note that there are many types of SSD, the dominant ones are SLC, MLC, TLC, and QLC. T work mostly in the same way, but the cost and longevity differs. Here’s a video that may help you understanding the difference between the TLC and QLC ones. Security. As mentioned in the above point, because SSDs don’t delete data when you delete them and writes data to an empty block, it’s less secure when you format it. When you delete something from either SSD or HDD, you can retrieve it back because the data doesn’t get deleted immediately. But if you write zero bytes to an HDD and fill it up, it will overwrite all the data. But that doesn’t always happen to an SSD. For SSDs the data is written to an empty cell, which may keep the deleted data. And also writing too much data to an SSD isn’t a good choice! So be careful while selling out your old second-hand SSD. Conclusion. In today’s world, both SDD and HDD are reliable. SSD are getting cheaper like never before! So it’s a perfect time to replace your old HDD with an SSD from a reputable brand and enjoy the speed of the SSD, just keep in mind not to write too much stuffs like an HDD. You may prefer getting an expensive one (not the QLC ones) if you are a power user… Hope this helps!