Sunday, May 20, 2012

Memory Guide

Memory Guide

Storage Devices


The Computer Storage is use for Store and Retrieve Information. Important factors in storing and retrieving information are the type of media (Magnetic, Optical ,MO), or storage device, used to store information; the media’s storage capacity(KB, MB, GB or TB) ; the speed of access and information transfer to and from the storage media bps, Kbps, KBps, Etc) ; the number of times new information can be written to the media (Read only, Write Once, Rewritable, Read and Write) ; and how the media interacts with the computer (PNP, Hot pluggable ) .

Information storage can be classified as being permanent (ROM, CD ROM) , semi permanent (Floppy Disk) , or temporary (RAM, Cache Memory) . Information can also be classified as having been stored to or retrieved from primary (RAM, ROM)or secondary memory (Magnetic, Optical ,MO).

Primary memory, also known as main memory, is the computer’s main random access memory (RAM). All information that is processed by the computer must first pass through main memory.
SIMM Memory

Types of Memory

1. Registry
2. Cache Memory –L1,L2
3. RAM
            I. SIMM -30 Pin/73pins          – 50ns,60ns
A.    SD RAM   -168pin            -66MHz(Pc528) Speed -100MHz(Pc800)- 133MHz (Pc1064)
B.     DDR SD RAM-184pin     -266HMz(Pc2128) Speed-333MHz(Pc2700)-400MHz(Pc3200)
C.     DDR2       -
D.    DDR3       -
III.RD RAM               -184pin-600MHz(Pc1200) Speed-800MHz(Pc1600)

Secondary memory is any form of memory other than the main computer memory, including the hard disk, floppy disks, CD-ROMs, and magnetic tape.

1.      Magnetic Media                      a. Floppy Disk (640KB-2.88MB)
b. Hard Disk (IDE/SCSI) – (1GB-2TB)
c. Zip Disk (100MB-250MB)
d. Tape Drive(2TB-16TB)
2.      Optical Media             A.        CD ROM/CD RW (250MB-800MB)
B.        DVD ROM/DVD RW (4GB-16GB)
C.        Blue RAY (10GB-40GB)
3. Magneto Optical Drive (MO Drive)           A.        Supper Disk
                                                                        B.        Jass Disk



Floppy Disk



Hard Disk Drive
4. Other Types of Storage Media

1. Flash Drive

Another type of storage media, called a flash memory, traps small amounts of electric charge in “wells” on the surface of a chip. Side effects of this trapped charge, such as the electric field it creates, are later used to read the stored value. To rewrite to flash memory, the charges in the wells must first be drained. Such drives are useful for storing information that changes infrequently.  

The first type of flash drive will contain single level cell memory. What this means is that it can sustain about 100,000 write cycles, meaning that you can erase and write over it 100,00 times. You will find that this can hold a great deal of information over time and that if you are looking for a device that will really go the distance, this could be exactly what you are looking for.

When you are looking at flash drives, they come in many different formats:
The first one that you may be most familiar with is a USB flash drive. A USB flash drive will let you plug the small drive directly into your computer and you will be able to access it as a drive on your computer. It's Hot Pluggable .You can Plug and remove the drive without shutdown the PC, Laptop, or any device. This will allow you to copy information to it as you need to and you will find that there are plenty of reasons to stop and take a look at your data need to see what device will suit best.
Here are some common designs available for USB Flash drive:

The Twister:

With its 360-degree rotating feature, it eliminates the use of cap for USB Flash drive protection. Hence, there''s no more cap to lose. Most twist USB flash drive designs include a small split ring on its end to allow easy attachment to keys or a neck strap.

The Lizard: 

This refers to the USB flash drive that doubles as a flexible wristband. This is a very fashionable design as it is carried by popular USB flash drive brands in a number of colour selections, making it popular among young costumers. Its brandable areas make it a great promotional device.

The Cap less:

It is important for everyone to make sure that his or her flash drives have long life. The capless USB flash drive has presented a fashionable and practical alternative to capped memory sticks. The capless design is primarily focused on creating sleek and sturdy USBs that are easy to use and store.

The MP3 players:

Talk about multi-functional USB flash drives, these are cheap alternatives to branded MP3 players. Depending on the application features, this line of USB flash drive is compatible to popular audio file format such as the MP3, WMA and WAV files.

USB Pens:

This multi-functional and EPOS-enabled USB flash drive design delivers the benefits of a digital pen with full flash memory capabilities. When used with compatible software, it allows its users to enjoy a portable writing and sketching tool that also captures and stores written and drawn files in real-time speed.
Difference between a flash drive and a thumb drive

Flash Drive A flash drive is a compact USB memory drive that acts a lot like a portable hard drive. You can store data on it, as well as, transfer it from computer to computer. They are able to hold a great deal of information, but they do come in different storage sizes.

Thumb Drive- Thumb drives are like digital lock boxes. They come with a write protection feature. This is just a switch located at the bottom of the drive that when it is unlocked, you are able to write data to the thumb drive, but when it is locked, you can only read data from the drive.


Zip Disk

MO Disk

LS 120


USB Flash Drive


Micro SD with 
SD Adapter

Mini SD with 
SD Adapter

XD card

2 . Memory Card

Most electronics now use memory cards for data storage, including expandable memory slots to increase existing memory on certain devices. Available memory slots on a digital camera, phone or PC tablet may actually be a deciding factor for you when shopping for these electronics. To help you, here are more details comparing the common types of memory cards these devices may use.

Multimedia Card: This is one of the oldest memory cards around, and is used in many devices. You can use Multimedia Cards (MMCs) in SD card slots because they have a similar form factor. Multimedia Cards can carry up to 32GB of data. MMCs also come in smaller versions for mobile devices.

SD cards: These memory cards are currently the most dominant form of flash memory for portable electronics, fast replacing a lot of the other formats on this list. If your devices support SD cards, you'll have no trouble finding compatible cards for a long time. SD memory cards cover a whole family of Secure Digital cards with different storage capacities and read/write speeds.
Types of SD Cards
  • SD: SD memory cards carry up to 4GB of data. For additional storage, you may want a SDHC card, which can store up to 32GB. SD cards can be used in Secure Digital High-Capacity (SDHC) slots, but the opposite is not true.
  • miniSD: This is the smaller version of SD memory cards, used in phones and other small devices and also holds up to 4GB. miniSD cards can be inserted into an adapter and read using a regular SD card slot. Like SDHC memory cards, miniSD has a higher capacity version, known as miniSDHC.
  • microSD: Even smaller than the miniSD, a microSD card can hold up to 2GB. microSDHC cards can hold up to 32GB.
  • SDXC: Secure Digital Extended Capacity (SDXC) memory cards carry up to an incredible 2TB of data (equal to over 1,000GB). SDXC memory cards fit into regular SD and SDHC slots, but require an SDXC slot to function.
  • xD cards: xD-Picture Cards are almost exclusively used to store digital photos in cameras by certain manufacturers. Because not all memory cards are compatible with all cameras, xD memory cards come in different formats (M, H and M+).
 CompactFlash cards: Some digital cameras and camcorders use CompactFlash (CF) memory cards, with storage capacities up to as much as 100GB, though 16GB or smaller is more popular. Because CompactFlash has been around for a while, you'll want to check which version your camera is compatible with before you buy. 

Memory Stick cards: The Memory Stick memory card family offers multiple formats, including Duo, Pro, Micro and XC. Storage capacities vary among the different memory cards. These flash memory cards are typically used in cameras, computers, PDAs and some portable gaming systems.

Micro SDHC

Memory Stick Pro

Memory Stick Pro Duo

Multimedia Card

CF Card

Digital Camera

Memory card readers

A memory card reader is one accessory that is a must-have for every digital photographer. They offer great benefits in convenience and operation that make them well worth the modest purchase price- usually under $20.

Memory card readers are convenient because you can connect them to an open port on your computer and just leave them there. Whenever you want to download pictures, just take the card from the camera, place it in the card reader, and away you go! Most new computers will recognize a memory card reader without installing any special software, so you probably won’t have to worry about installing software to use it.
Downloading pictures from your camera requires it to be turned on, which wastes battery power better used for picture taking.   The flimsy cord that connects the camera to the computer is easy to misplace, as well.

Most card readers use a USB connection. If your computer has a USB 2 or FireWire port, you can buy a high-speed card reader that will take advantage of the faster connection and download your pictures even faster.

Users of digital cameras have two options when it comes to accessing their photos – a direct connection between the camera and computer or using a memory card reader. The first option involves connecting your camera to an available USB port and accessing the memory card through the camera. The other – and faster - option involves using a memory card reader that also hooks into your computer via USB and reads the memory card independently from the camera.
Memory card readers provide a convenient way to access your photos by acting as a drive in which you can insert your memory card. It can be used to read, copy, and backup data on the card. In addition, by using it, you will conserve the battery life of your camera.

Super Media Store stocks memory card readers which hook into an available USB port and read a wide variety of memory card formats including Secure Digital and Multi Media Card.

Mobile Phone

Multi card Reader

Multi card Reader
Flash Drive- Twister

Flash Drive- Custom Type
Flash Drive- Wrist Band

Difference between a Smart Media card, a Compact Flash card and a SD media card

All three are memory cards, but they do not have any real similarity beyond that. They are different sizes and shapes and totally incompatible with each other.
SD and Compact Flash are now the commonly used cards. Compact Flash cards, while larger in physical size than SD cards, tend to be much less expensive and available in a greater variety of speeds and sizes.

Smart Media is becoming obsolete and is not used in recently-introduced digital cameras.
SD/Micro SD/Micro SD HC
micro SD is the smallest portable memory card available, in terms of physical dimensions, but it can store up to 4 gigabytes (GBs) of data.

  HC stands for "High Capacity." An SDHC card may go up to 64GB but can be as little as 2GBs. This causes some confusion because there are some non-HC SD that come in 2GB and 4GB varieties
        This causes a problem when one attempts to use a micro SD card in a micro SDHC card slot. These two technologies are not compatible. Unless the memory card is labeled "High Capacity" or "HC," it will not work with an HC slot.

        However, a micro SD card can fit in a mini SD or regular SD slot, if you use an adapter. While a micro SD card is not compatible with a micro SDHC slot, it is compatible with mini SD and regular SD.

        The next step above HC is XC, which stands for "Extra Capacity." This format is designed to offer up to 2 terabytes of storage space, or 2048 gigabytes. The transfer speeds are expected to increase from 104 megabytes per second (MB/s) to 300 MB/s.

        As of the date of publication, SD cards come in three categories: SD, SDHC and extra-capacity SD (SDXC). SD and SDHC cards come in standard-, mini- and micro-sized formats, which are distinguished by their physical dimensions. Presently, SDXC cards, which offer between 32GB and 2TB of memory, are available in SDXC and micro SDXC formats only. 

Micro SD and micro SDHC cards are commonly used in cell phones and smart phones. For instance, the BlackBerry Curve 3G 9330 supports both card types for up to 32GB of expanded memory. You can identify which SD card is which by looking for their designation and capacities, which are clearly labeled on each card.

SD memory cards are conveniently portable and neatly compact, so much so, that if you're not careful, you could easily lose them. SD, SDHC and SDXC cards are about the size of a postage stamp, measuring 0.9 inch wide, 1.3 inches long and 0.08 inch deep, and weigh 0.07 ounce. 

MiniSD and mini SDHC cards are about a third of the size of SD, SDHC and SDXC cards, measuring 0.8 inches wide, 0.8 inch long and 0.06 inch deep, weighing 0.03 ounce. At 0.02 ounce, micro SD, micro SDHC and micro SDXC cards are about the size of a fingernail and measure 0.4 inch wide, 0.6 inch long and 0.04 inch deep.
        In relation to recording video, which most cellphones and smartphones on the market are capable of, SD cards, in all their varieties, are subdivided into two categories: Ultra-High Speed Class and Speed Class. 

The SC is subdivided into speed classes -- Class 2, 4, 6 and 10 -- that are compatible with normal or high-speed bus interfaces. The UHSC contains just one class, Class 1, that works with ultra-high-speed bus interfacing and is compatible with only SDHC and SDXC cards. Each SD memory card, including the microSD and microSDHC cards used in cellphones, is compatible with the SC subclasses.
        All types and formats of SD cards, regardless of their manufacturer, are built to the standards established by the SD Association, an international organization comprised of electronics-related companies throughout the world. 

Established by SanDisk, Toshiba and Panasonic in 2000, the SDA currently has more than 1,000 members. SD technology is used in more than 8,000 products worldwide, including cell phones, digital cameras and video gaming consoles. SD cards are designed to not only be used by devices produced by different companies, but between different types of devices, as well. 

For example, video recorded on a mobile phone, such as the HTC Desire, can be played using the Nintendo Wii by inserting the phone's micro SD or micro SDHC memory card into the console's card slot.

        When deciding between a Class 6 and Class 4 Micro SDHC memory card, consider the intended application. Class 2 cards are recommended for standard definition video recording and low resolution digital cameras. 

These applications require the least amount of transfer speed for affective use. Class 4 cards are recommended for HDTV video recording. Class 6 cards are recommended for professional video cameras and DSC consecutive shooting. 

 Class 10 cards meet the specifications for full HD video recording and HD still consecutive shooting. HD video and HD photography require the highest data transfer speeds because the resulting file sizes are larger than traditional SD files.
        Speed class specifications were originally established with video recording in mind. Many camcorders, video recorders and other devices require constant and reliable transfer speeds to function properly. 

This has become more important with the advent of high definition video and high resolution digital cameras. By designating a minimum data transfer speed for each class of card, manufacturers can ensure compatibility with a multitude of devices.

        The choice between a Class 6 and Class 4 Micro SDHC card should be determined by the intended use. Most manufacturers will recommend which class to use for their products. 

This guarantees optimal user experience and performance. If a device designed for Class 6 Micro SDHC cards is using a lower speed class card, the result could be corrupted data or dropouts. 

Cameras may experience lag between shots while the image data is being written to the card. Digital cameras equipped with consecutive shooting or burst mode should opt for higher speed class cards to avoid such situations.

Currently in market there are in all 12 different types of memory cards available in market. They are as follows:
  1. xD
  2. TransFlash
  3. Smart Media(SM)
  4. Mini-SD
  5. SD (Secure Digital)
  6. RS-MMC (Reduced Size MMC)
  7. MMC (Multimedia Card)
  8. Memory Stick Pro
  9. Memory Stick Duo
  10. Memory Stick (MS)
  11. Compact Flash Type II
  12. Compact Flash Type I.
You will be just astonished by this list. This memory cards are classified on basis of there cost, physical size, reading and writing speed, storage capacity. 
Given below is the classification given based on the above parameters; 


SD, MMC, Compact Flash are cheaper than other memory cards but this is sole factor related to market. If for example we will consider Memory Stick Card, now all the rights related to these cards are with Sony. So they decide the price of this card for other companies like SanDisk want to manufacture them. 

Physical Size

Compact Flash is the memory card which has the largest physical size, and XD, TransFlash, Mini-SD, RS-MMC are the smallest in case of physical size.

Reading And Writing Speed

When your data is saved on the card the gadget or the appliance using it writes the data onto it. Now reading and writing speed are different for different memory cards. Following is the table which illustrates the read and writes speed for different card for a data of capacity 28 MB; 
Type of Memory Card
Read Time
Write Time
35 seconds
56.6 Seconds
Smart Media
35.7 seconds
1Min 2.2 Seconds
34.8 seconds
1Min 6.7 Seconds
So looking at the table above it is clear that MMC card is the fastest of them all. But this table is just to clear the idea; the timing may vary according to the manufacturers. 

Storage Capacity

Earlier 32MB and 16MB capacity cards were common, but now the capacity has increased to 4 GB. Today you will not see 256MB or 512MB card also easily, 1GB cards are the most common. This is the needs of today. If we consider a basic digital camera with resolution of 4 Mega pixels then each snap taken will be of size 1.5-2MB. Now just think if you are using 32MB memory card, at the most you can store 16 photos in the card. Now imagine how many times you have to empty the memory card. So as the need increases the storage capacity of the memory cards also increases.
So now the difference between the memory cards must be cleared to some extend. While purchasing the memory card you just have to keep all the above parameters in mind and choose the memory card which is the most suitable for meeting all your requirements. 

Data Source,,, http//  EncartEncy

1 comment:

  1. Do you have any idea of this artical please share here.