Storage Devices

in this video from it free training I will have a look at storage devices storage devices are what hold our customers data our customers rely on this storage to help keep their data safe loss of data may result in loss productivity or the work may never be able to be recovered thus it is important to keep it safe before I start having a look at storage devices I will first have a look at the hierarchy of storage understanding this will give you an idea of what you were trying to achieve with each of the different storage types to start with I will look at primary storage primary storage is used to run software and store data that the computer needs to access quickly there is a small amount found in the CPU in the form of registers and cache registers are small amounts of data that are used by the CPU for calculations cache is the fast second copy of some of the computer's memory used to improve performance this memory may be fast however when the power is Switched Off the data is lost thus this storage is often referred to as volatile the next storage I will look at is secondary storage secondary storage is in the form of your hard disk drives Optical drives and flash drives essentially this is storage that is easily accessible by the computer even if the storage is not always online such as the CD ROM or flash drive it is still easily accessible very quickly the advantage of this storage is that it keeps its data when the power is Switched Off also price-wise this storage costs less than primary storage does so essentially you can have more of it compared with primary storage the disadvantage is this storage is slower than primary storage since secondary storage is slow compared with primary storage it is difficult to work with directly and so will generally be swapped in and out of the computer's memory as required the last storage I will look at is tertiary storage tertiary storage is offline storage in the old days it was quite common to have a large room full of tapes or other storage media this was generally used for physical long-term backups you don't tend to see this as much nowadays a lot of companies in order to protect their data will use an off-site storage location in case the primary site is destroyed by an environmental disaster having storage like this requires someone to be employed to get the storage media when required and loaded into a drive as technology got better this manual process was replaced by robots the robot will retrieve the storage media and load it into a device either way there is a delay from the request to when the storage media can be loaded into a drive to access as before the information from tertiary storage is transferred to and from the computer nowadays we are finding that a lot of these types of storage is being replaced by cloud storage cloud storage is always available and since it is offsite it protects the organization from data loss if the computers on site are lost for any reason there's also cloud storage that is only available at certain times or on request for example Amazon Glacier storage this storage can replace off-site backups and is a lot cheaper than storage that is always available online at the top of the hierarchy this gives the fastest speed but the highest cost for data as you go down the hierarchy the price for data Goes Down And also the speed you can access the data goes down you can see the trade-offs between the different types of data storage I will next have a look at the different types of storage devices that are available to start with I will look at hard disk drives HDD hard diss were developed in 1956 they started to be used a bit more in the 60s and as time passed became very commonly used in computers the first hard diss were very large as time went on they got smaller and smaller a typical hard disk nowadays is 3 and 1/2 in in size for laptops or small devices there's also a 2 and 1/2 in hard disk this is just a smaller version of the larger hard disk they are generally slower and have less storage capacity than the larger hard diss this small size makes the popular in laptops and nowadays solid state drives have replaced these smaller hard diss in a lot of cases hard diss work by using magnetic storage to store data essentially the media inside the hard disk is made of a magnetic material the magnetic material can be read or it can be changed this allows data to be stored on the hard diss for long periods of time even if the hard disk does not have power let's have a closer look although there are a number of different manufacturers of hard diss the basic design Remains the Same the hard disk contains one or more platters each platter is made of a strong material to give it strength and then has a thin magnetic layer applied there may also be other layers applied to protect the platter from damage the platters are spun at high speed in order to read the data on the platter a read right head is used the this head will read data on the platters or modify it as required in order to read or write the data an actuator is used which moves the head across the platter this allows the head to read and write data anywhere on the platter now that we have a basic idea of how a hard disk Works let's next have a look at what to look for when selecting a hard disk the first consideration generally when purchasing a hard disk is most likely the size of the hard disk this is the amount of data that will be able to be stored on the hard disk you can see in this graphic that hard disk capacity has been increasing as time goes on back in the 90s hard disk capacity was measured in megabytes it was not until the '90s that hard disk capacity went over 100 megabytes nowadays hard diss mostly start in the gigabytes as time goes on the minimum size keeps going up later in the video I will look at the reasons why when this video was created the largest hard diss on the market were over 20 terabytes hard disk technology keeps improving and it is estimated that with improvements in hard disk technology one day we could have hard diss as large as 100 terabytes on the market the next consideration of hard disks is the transfer rate this will be determined by a number of factors generally the hard disk manufacturer will provide different data rates and will will provide the maximum data transfer rate that is achievable keep in mind that a hard dis requires a head to be moved across the platter to access the data if the data is spread all over the platters this process takes longer as the head has to move over the platter to locate the data moving the head is referred to as the seek time the bigger the seek time the longer it will take to locate data and thus a slower average transfer rate keep this in mind as a hard disk with a fast transfer rate but a slow seek rate will perform slowly if the data on the hard disk is being accessed randomly for example if the hard disk has a lot of small files on it if data is being accessed sequentially for example playing a large video file the transfer rate will be more important than the seek time the next consideration is the speed and interface of the hard disk the platters in the hard disk spin at a certain number of revolutions per minute or RPM when the head of the hard disk moves it will need to wait in the required position until the data it wants to access is under the hard disk hit the faster the hard disk spins the less time it will need to wait for the area containing the data to be under the head also if the hard disk is spinning faster this means more data can potentially travel under the head in a shorter time period making the hard disk transfer faster it is harder to read data at faster speeds so faster spinning hard diss tend to have lower capacity the hard disk will also have an interface that is used from the computer to transfer data it is important to consider the interface that is used to transfer data to and from the hard disk the interface will support a maximum amount of data it is important to consider this because if the interface does not support the maximum speed of the hard disk the hard disk will underperform for example if a hard dis is sata 3 but the interface on the computer is SATA 2 the hard disk will be limited to performing at SATA 2 speeds keep in mind that the faster the hard disk spins also will affect the reliability of the data on the hard disk and its lifespan this brings us to the next consideration which is reliability and data Integrity the hard disk manufacturer will give you some specifications that will indicate how long the hard disk is likely to last last some manufacturers design different hard diss for different purposes for example hard diss with low use may be designed to use less power hard diss that are constantly under load may be designed to last longer but cost a bit more if you are using a hard disk in a data center you will most likely want a hard disk that is more reliable for the home computer saving a little bit of money may be more important to the buyer than the reliability of the hard disk the manufacturer May also release a failure rate this specification will give you an indication of the probability of the hard disk failing and is generally given as a percentage per year before I look at other storage devices I will first have a look at the future of hard disks this will give you an idea of your future planning and what you should consider using hard disks for the first thing to consider about hard diss is the base cost per unit this includes the case the motor and electron essentially this means that the basic parts of a hard disk come with a cost regardless of how much data the hard disk can store the base cost does not change you can see why we don't see very small capacity hard diss on the market if you're going to pay for the parts of the hard disk you're going to at least put a decent amount of data inside to offset the base cost given this design of hard disk has been around for a long time it would seem more likely the basic design will remain the same however what will change is the technology inside it we are starting to reach some hard limits with how much data can be packed onto a single platter to get around these problems some other changes have to be made one of the changes is filling the hard disk with helium rather than air the advantage of this is that helium causes less turbulence and friction than air does this means that more pla can be added to the hard disk allowing for greater capacity the downside of this is that helium is very difficult to contain if you consider a helium balloon the balloon will float because it is lighter than air however as time goes on the helium will escape from the balloon and the balloon will no longer float you may be thinking why not make the hard dis in a vacuum the reason is the heads of the hard disk basically float on the platter as the hard disk spins that air or helium pushes the head upwards this causes the head to float in close proximity to the platter without air or helium in the hard disk the head would hit the platter of the hard disk and would not work the other downside of a helium filed hard disk is the extra difficulty in manufacturing them makes them expensive to build for these reasons you won't see many of them on the market maybe in the future we will see more of them on the market there are also other improvements we may see in the future one promising approach is Hammer this stands for heat assisted magnetic recording Hammer uses a laser to heat the platter before the head performs a right essentially to store a one or zero on the platter requires magnetic material to be turned to a particular position one position for a one and another for a zero heating the platter beforehand allows the magnetic material to be positioned with more accuracy this allows more data to be stored on the platter the downside of this approach is it is expensive to build and has low reliability although heating the platter holds the heat for a split second long enough for the head to write to the platter the process can damage the platter over time although a promising technology and some hard diss on the market use it it looks like it is starting to be phased out but only time will tell the next promising technology is mammer this stands for microwave assisted magnetic recording this is essentially the same idea as Hammer however to heat the platter a spin torque isolator is used this is cheaper and has greater reliability than using hammer as time goes on technology improves and we will have to see which technology ends up being used you never know which way technology will go it appears the trend is for larger capacity hard diss which is still the cheapest option with new technology it is unlikely this will change anytime soon some have predicted that there will be 100 terabyte hard diss by 2030 will this happen maybe only time will tell although hard diss have been in use for a long time the seek time that is the time it takes to move the hard disk head has caused Random Access of data on the hard disk to be slow the next technology that I will look at addresses this problem solid state drives address the limitations of hard disk drives solid state drives or ssds use integrated circuits since they use integrated circuits there are no moving Parts generally ssds use flash memory to store data you can see here the inside of an SSD drive there will be a number of chips that store data on them there will also o be one or more additional chips which are the memory controllers which control reading and writing on the chips ssds entered the market in 1991 and were originally better for random reading while hard diss still performed better for sequential reading with improvement over the years solid state drives now outperform hard diss in both random and sequential reading there are some disadvantages the cells that contain the data in a solid state drive wear out the more they are used also capacity wise solid state drives cost more per bite than hard diss do essentially the more you write to one cell in the SSD the more chance it has of wearing out and not working anymore a modern SSD will attempt to even out the writing of cells so all the cells are written to equally if a cell is being written to significantly more than others it will wear out faster the performance of SSD drives will slow down when they are almost full this is not a problem with hard disk drives the reason for this is that SSD also uses blocks to store data when writing data to a block the block may not be completely used when an SSD has lots of free blocks this is not a problem since it simply puts the new data in an unused block when all the blocks are partially full this is not possible so the SSD drive has to do some rearranging in order to write the new data think of it like you have shelves on which you store items in boxes when you have free boxes you can just put the items in the boxes and place them on the shelves this is not making efficient use of the spaces in the boxes sooner or later the shelves will get full and the only way to get more items on any shelf is to rearrange the items in the existing boxes to fit new items in this involves taking the boxes off the shelf rearranging the items and putting the boxes back on the Shelf to put this in SSD terms an SSD drive with free blocks to write new data will take one right command if the SSD is becoming full it may need to read a block add the new data to that block and then write the block this means there is a read and write command rather than just a write depending on how the data is laid out it may even take more operations if it has to rearrange data from multiple blocks modern operating systems when not underload will rearrange the data on an SSD to make it more efficient at writing new data however it won't do this while underload you can now see why it is advisable not to completely fill a solid state drive although opinions differ attempt to keep utilization between 75% and 90% to get the best results less is better if the SSD is being written to a lot SSD drives like the ones shown were a great first step however the performance has become so good that SSD drives can outperform the SATA interface and protocol the sata 3 interface is limited to 600 megabytes per second which SSD drives can now outperform hard disk were originally designed using one head so the protocol was designed with that in mind an SSD on the other hand has multiple chips so it is possible to access multiple chips at the same time something the protocol was not designed to do let's have a look at the next technology that addresses these problems to address these issues with solid state drives a new technology called m.2 was created the formal name being next gener generation form factor or ngff rather than using a cable to connect the drive the storage is plugged directly into the motherboard for solid state there are two different versions the newer version being m key which uses the protocol nvme and stands for nonvolatile Memory Express the Keen refers to a notch being taken out of the board as shown in the case of m key the Notch is in a certain position there are 12 different positions this Notch can be located however in the case of solid state drives only two are used at least for the moment m key supports four PCI Express Lanes it also supports SATA and SM bus devices your motherboard will need to have an adapter that is the same key as the device shown here you can see the notch lines up with the adapter on the motherboard high performance m.2 storage will use m key this is for two reasons firstly it needs the extra bandwidth that having four PCI Express Lanes provides second to this the nvme protocol was designed with solid state devices in mind so will give better performance m key seems to be the current standard used for motherboards on Old Computers you may find a b key used however this is not the only thing you need to consider an m key will most likely support PCI Express as its interface this means the computer needs to also support this interface older computers may not support this or may have only limited support for example it may not support booting using PCI Express so to have backwards compatibility b key can be used b key is compatible with the SATA interface so essentially should work with older computers the computer will see the storage as a SATA drive and not a PCI Express Drive thus the interface won't be as fast as PCI Express and the protocol will be the older protocol so the problem is how do you keep backward compatibility but also allow for newer m key devices to be used the solution is B+ m key storage devices that use this connection have both a b key notch and an m key Notch this means that it can be put into a connector that is either a b or m key you will find that on the market the m.2 storage will be m key or B+ m key this way we can use m key on motherboards that support it since B+ m key has both notches the storage devices can be used in either m key or b key motherboards the advantage of using this connector is that we now have storage that is Backward Compatible with older systems but can still be used in newer systems the disadvantage is that due to having two notches this reduces the number of pins on the connector this means that when using PCI Express the storage will be limited to two PCI Express Lanes if you want maximum compatibility purchase an m.2 storage device with The b+m Notches if you want performance then purchase the m key version however check to make sure that the computer you are putting it in will support it if it does not fully support it you may need to make changes in the Bios in order to use it or it won't work at all the last consideration is the size the size will be given as width followed by length this will be in millimeters for storage they all basically start at 22 mm wide and thus start with 22 the length can vary in this example the length is 80 in order to use it make sure the motherboard has the correct screw holes if you're not sure the screw holes will generally have the size next to them solid state driv started out being very expensive however the cost has come down significantly hard diss are still the cheapest option however I will next look at a technology that was briefly around when solid state drives were still still very expensive hybrid drives or sshds are essentially a hard disk combined with a solid state drive the solid state drive is used for frequently used data a hybrid Drive will look just like a regular hard disk inside the hybrid Drive will also look just like a hard disk what is different is the circuit board inside the hard disk if you compare this with a regular hard disk circuit board you can see the extra chips on the circuit board these extra chips are the flash memory and also controller chips for the solid state part of the drive frequently used data will be kept on the flash memory basically the hybrid Drive is attempting to keep a cached copy of the most used data on the solid state drive for higher access speed when hybrid drives were developed solid state drives were very expensive the idea of hybrid drives was a trade-off between cost and performance however they were not on the market for long they are not sold anymore due to the reduced cost of an SSD nowadays rather than buying a hybrid Drive most users will purchase a solid state drive to run the operating system in data since this will give them the biggest performance boost if this is not enough space they will add a hard disk drive to the system to increase its capacity or even a second solid state drive it is just a matter of the user making sure the data they want to access quickly is on the solid state drive so far I have looked at storage that does not have changeable media I will next look at storage that does have changeable media the first changeable media storage that I will look at is optical disc there have been many different types of optical discs released over the years most of which have now disappeared with a few still in use I will cover the main ones since they are the ones you're most likely to come across the first one is CD or compact dis CDs have been around since the80s they have an upper capacity of 700 megabytes it is possible to get small siiz CDs like 640 megabytes due to it being old technology most manufacturers just sell the biggest size as the price difference and demand is not much there were other standards such as laser dis however they were never widely adopted in 1996 DVD was released which stands for digital versatile disc or digital video disc there were other standards available as well one of the more notable being HD DVD for those of you who are old enough you may remember the VHS and beta format were in the late '70s and early 80s consumers had to choose between different formats with VHS eventually winning out over beta but consumers don't like having to choose between different media and hoping for the best so HD DVD although a good format was dropped early on so the industry could put their efforts behind just one format DVD holds 4.7 GB on a single layer or 8.5 GB with two layers two

layers essentially means there's a second layer of data that can be written to this is achieved by the the laser refocusing to access the second layer the downside of this is that if you are watching a movie there may be a pause in the playback while the DVD player is refocusing its laser DVD turned out to be very popular in 2006 the next generation of optical disc the Blu-ray was released there were other formats however Blu-ray was the only one widely adopted and that has been slow I'll explain why in a moment Blu-ray provides 25 GB of storage on a single layer and 50 GB of storage on Dual layer this is a big improvement over DVD however the problem with its adoption was that DVD already provided good quality movies although Blu-ray is better consumers were reluctant to switch to the New Media due to the extra cost over DVD and with only a small perceived Improvement in quality most customers were happy with the quality they got from DVD at the time and did not want to pay more for this small perceived quality improvement this was not such a problem when moving from CD and earlier media because the Improvement was more noticeable Blu-ray has been on the market for over 10 years now and really due for something to replace it however nothing has this is mainly because Optical media is being phased out by online services with online Services offering video up to 4K which is easy and convenient to access there is not as much demand to purchase Optical media since there's not much demand it is hard to make money from Blu-Ray so a replacement for blu-ray is not really likely currently on the market in the game industry there are consoles that use Ultra HD Blu-ray and some movies that are also available in that format if you want to play movies back at 4K you will need to purchase this format Ultra HD Blu-ray provides 50 to 100 GB of storage so about twice that of Blu-ray not bad but in the future we are likely to need more although no winner for a replacement format is clear at the time this video was created the one that shows the most promise is archival dis this format provides from 300 GB up to 1 terabyte of storage there are devices is available on the market that can read this format however it appears at least for the moment they are aimed more at backup storage And archiving whether this technology is used for published media on this Optical medium later on only time will tell now that we are on the topic of archiving this brings me to the next storage device before I start I will first point out that tape drives are not currently on the CompTIA A+ exam objectives however I will will cover them briefly because they are still often used in companies for backups even if they are currently not being used many companies will have years of backup tapes which you may need to access in order to retrieve some lost data tape drives nowadays generally come in a plastic case with a tape contained inside the tape is inserted into a tape drive in order to be read or written to since the tape has to be wound to the required location the tape can only be read or written to sequentially for example if the data you require is at the end of the tape the tape will need to be wound to the end in order to access it thus it is a slow process to seek to the required location but once found reading and writing can be done quickly since data is not available quickly tapes are generally used for backups And archiving many companies if they use tapes will purchase an autoloader and Auto autol loader as the name suggests will automatically load tapes in as required in this example the autoloader will hold 16 tapes different autoloaders will have different capabilities for example some may have robots that can access a large storage area of hundreds if not thousands of tapes some autoloaders will also have multiple tape drives tape systems like this may require tapes to be inserted and removed on a daily basis for example if your site has requirement to have off-site backups the tape drive may require tapes to be removed each day in order for them to be taken offsite you may also need to put tapes in some autoloaders will have barcode readers so you know which tape is in the drive your job may involve swapping tapes out as required there are a lot of Technologies on the market that change the way that we store data tapes are not used as much as they used to be for example some companies are storing their data in the cloud rather than using tapes this meets the need to have an offline backup and storing in the cloud can be a lot easier than having to worry about changing tapes every day with people working more at home it makes sense to have data in the cloud the largest storage currently available on a single tape is 300 tabt if tape drives can continue to store large amounts of data for a cheap price we may still continue to see them used in the future however it fa is stiff competition from other Technologies only time will tell if they keep getting used or become obsolete the last storage device that I will look at is USB flash drives USB flash drives are small and reusable old flash drives contain a controller and flash storage the controller will control how the data is stored on the flash memory in the flash drive this takes up a little extra room in the flash drive but not much when this video was created the largest USB flash drive was 2 tabt in size with a prototype of 4 terabytes being tested who knows how large these devices will get but at present you can store a lot of information on them and keep the flash drive in your pocket making it easy to transport to make the storage even smaller the controller and interface can be removed leaving only a small card containing the flash memory these are called SD cards these come in a number of different sizes with SD being the largest followed by mini SD and then micro SD the size does not make a difference on how they work in fact some SD cards will contain an adapter so they can be used in different devices for example a mini SD card may come with an adapter to convert it to SD size this is just a matter of using the right card in the device or if the SD card is too small using an adapter to convert it to a larger size you won't be able to get an adapter to make it smaller for obvious reasons since SD cards do not have a controller they need to follow a particular standard in order to be used in the device the standard they follow will also determine how much data they can store shown here are the different standards and how much data they can store in order to use SD cards your device needs to support this standard generally you will will find that the manufacturer may not say which standard they support and instead give you a maximum capacity the device will support generally you need to make sure the SD card you purchase does not store more data on it than the device supports devices are generally Backward Compatible so you don't need to worry about what type it is just make sure it is the maximum size or less that concludes this video on storage types in later videos I will have a look at some of these storage devices in more detail I hope to see you in those videos and I would like to thank you for watching

2023-12-30 17:34

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