As discussed in the previous article “Computers 101: ‘motherboard hardware-memory’, memory within your computer can be classified as either being short-term (temporary; volatile) or long-term (permanent; non-volatile). RAM, which is the memory installed on the motherboard, is considered to be temporary in that it is volatile, meaning when your computer loses power, whether intentionally (as in the case of shutting off the computer) or unintentially (as in the case of a power outage), all the information that it contained within it is lost. RAM was designed to operate in such a manner since it is only used to deal with the computers immediate task at hand.
However, the need for long-term memory exists as well. Long-term memory is considered to be non-volatile memory, meaning that it will not lose the information that it contains in the event of a power loss, and is critical for efficient computer operation. Long-term memory is where the BIOS, OS, application programs, games, pictures, documents, etc. need to be stored in order to allow them to be recalled whenever you want to use (or view) them. This information will always be the same unless it is altered, either intentionally (such as editing a document or photo and re-saving it) or unintentionally (such as inadvertently overwriting the file or the file becoming corrupted by malware or a virus).
There are several pieces of hardware or devices that are used as long-term storage. BIOS is normally contained within a dedicated ROM chip (IC) located on the motherboard, whereas all other information requiring permanent storage usually resides on a floppy disk, hard disk, or optical disk and can be read or recovered by using the appropriate drive type. Newer long-term storage devices include solid-state drives (SSDs), memory cards (such as those used by digital cameras) and thumb-drives (memory sticks that can be inserted in an available USB port).
There are several advantages and disadvantages associated with every type of long-term storage devices, but the three characteristics that most users are concerned with are its capacity, cost and speed. We all want the fastest method at the lowest cost, but in most instances, those two characteristics are at opposite ends of the spectrum. In other words, if you want high speed, then you will probably be looking at high cost. Conversely, if you are looking for the lowest cost, then you are probably achieving that by sacrificing operational speed. Remember that in order for your computer to be able to do anything (run a program or application, allow you to view or edit data, etc.), the appropriate program or data has to be loaded (transfered) from whatever long-term storage device it is currently stored on, into the CPUs working memory (RAM). As far as the capacity factor goes, as with everything else in life, the more you want, the more it’s going to cost.
Types of Long-Term Storage Devices
Floppy disk drives (FDDs) are already (or quickly becoming) a thing of the past for the most part. While they had the advantage of being able to provide portable storage via their removable disks, the FDDs had extremely slow data transfer rates and their disks were limited in the amount of information that could be stored on them, both being pitiful by today’s standards. If you have been working with computers long enough to remember using them, you will recall the delays encountered when running a large application program or game and being required to constantly remove one disk and insert another, as well as having to wait for what seemed like forever in order for the information to be transferred into the computer before you could continue to play your game or work on that document. Although many of todays motherboards still come with FDD connections, unless you have a specific need for having one, you don’t really need to include it in your build. The portability provided by the floppy disks have been replaced by CDs and DVDs as the storage medium.
Hard disk drives (HDDs) are the most common method of achieving long-term storage. This is where the operating system (OS) and all of your programs and data are stored. Unless you are considering using SSDs for your primary long-term storage needs, it is a given that you will need at least one HDD. HDDs capacity ratings typically fall in the 80 GB to 3 TB range. You will be hard-pressed to find anything smaller than a 80 GB HDD. As far as transfer speeds go, it depends on what style data connection you go for. Most modern HDDs use a data transfer connection called SATA (serial advanced technology attachment). There are currently three styles (revisions) of SATA HDDs: SATA1 or just plain SATA (up to 1.5 Gbits/sec operation); SATA2 or SATA II (up to 3.0 Gbits/sec) and SATA3 or SATA III (up to 6.0 Gbits/sec). As mentioned before, the larger the HDDs capacity, the more it’s likely to cost.
Optical disk drives (ODDs) serve as the modern mainstream device used for portability of information. Everyone is aware of just how easy it is to have music on a CD or a movie on a DVD and the ability to use the same disks in most any CD or DVD player. Many of todays application programs and games are still dependent on this portable medium for getting their product to the consumer, but many software providers are starting to incorporate the downloading of the software over the internet by a method called digital downloads. While in time this may make buying a CD/DVD disk to get software programs a thing of the past, users will still need or want the portability factor provided by optical disks. Memory cards and memory disks can be used for the portability factor in some situations, but as of this writing, they do not have the capacity of optical disks. Most ODDs use one of the SATA data transfer methods described previously.
Solid-state drives (SSDs) are a more expensive variation of HDDs. Whereas HDDs have moving parts associated with their operation which in turn can limit their maximum operational speed (data transfer rate), while contributing to the amount of noise they produce and the heat that they generate, SSDs have no moving parts. This makes them faster, more energy efficient and quieter in operation. SSD’s currently depend on one of the SATA data transfer methods described earlier. Keep in mind that with HDDs, the data transfer rate was up to a given rated speed. In actuality, the transfer speeds of HDDs are lower than the given SATA rates. SSD’s on the other hand, can achieve transfer speeds much closer to the maximum. The two main drawbacks associated with SSDs are their current cost and limited capacities.
Memory cards, memory sticks, thumbdrives and external HDDs depend on USB ports in order to transfer information into and out of the computer. Whereas SATA connections are normally used for data transfer between devices within the computer, USB (universal serial bus) ports are used to connect external devices to the computer and facilitate communication (data transfer) between the computer and the external device(s). As with SATA coming in several styles, the same can be said of USB ports. USB 1.0 (or 1.1) had a maximum transfer speed of 1.5 Mbits/sec (Low-Bandwidth) or 60 Mbits/sec (Full-Bandwidth). USB 2.0 (Hi-Speed) has a maximum data transfer rate of 480 Mbits/sec. USB 3.0 (SuperSpeed) can theoretically achieve transfer speeds of up to 5.0 Gbits/sec, but in actuality it is more likely to be closer to 3.2 Gbits/sec. As you can tell, USB speeds are much less than SATA data transfer speeds, which is why they are normally only used for devices that don’t require a hight data transfer rate (such as keyboards, mice, printers, etc.). Although external HDDs can connect to the computer using USB connections, these are typically only used to provide back-up copies of your other primary storage devices (internal HDDs and/or SSDs). Some external devices make use of another special connection called e-SATA (or eSATA). This type of connection allows data transfer speeds at SATA specs.
The amount and types of long-term memory devices you decide to employ in your computer design will vary, depending upon your needs or your budget. Most users will have at least one HDD and ODD. Advanced users needing or desiring better performance (or those that can afford a higher budget) may use a SSD to hold the OS and programs while using a HDD for mass data storage (saved games, pictures, videos, documents, etc) along with some type of ODD. Hard-core users may use multiple HDDs (or SSDs) to improve system performance or data storage reliability using a method called RAID.
Regardless of how many and which type(s) of long-term storage you decide to go with in your build, just make sure that the device’s connections are compatible with the motherboard’s connections. In most cases, ports and connections are backwards compatible, meaning if your motherboard has a SATA 3 connection, it will allow a SATA 3, 2, or 1 device to be connected (although it will only work at the devices rated speed). This applies to the USB ports as well. However, if you connect a SATA 3 device to a SATA 2 connection, then the SATA 3 device will be limited in its operation by the SATA 2 connection’s data transfer rate. If your motherboard will ony support SATA 2 transfer speeds, buying and connecting SATA 3 devices is a waste of money since SATA 3 devices tend to cost more than SATA 2 devices. This applies to USB ports and devices as well.