What is the difference between a phone's own memory and a phone card?

Terminology: The phone's own memory and mobile card

Mobile RAM, ROM, and memory cards.

First explain the relationship between the phone's RAM, ROM, and memory card. Both the RAM and ROM of the phone belong to the semiconductor memory. The ram of the cell phone is the memory that we often say, it is the abbreviation of random Access memory, that is Ram , can read and write data randomly when working state, lose data after power loss . The Rom of the handset and the traditional ROM (Read only memory) are somewhat different, it is divided into two parts, one for the system and the other for the user to store the data . And the memory card is very good understanding, commonly used has a TF card, used to store user data.

Ram

RAM is memory, the main mobile phone has 512M, 768M, 1G, 2G and other capacity, so some users say "16G memory" of course not refers to ram. The capacity of RAM is divided into nominal capacity, actual capacity and usable capacity of three kinds, the nominal capacity is we look at the capacity of mobile phone parameters, namely 1G, 2G these. The actual capacity will be less than the nominal capacity, which in addition to some small amount of loss (algorithm, particle difference), some phones will also be the GPU occupied a portion of RAM, so some 2G mobile phones will see the actual capacity is 1.7g~1.8g. And the usable capacity will be less than the actual capacity, is due to the system occupation and the background of the use of the reason, the general 2G mobile phone just boot when the available RAM will be about 1.3G, and 1G of the phone can be used to 400M around.

How to save Ram?

Save RAM mainly control the number of background programs, here is mainly for Android phone methods, iOS and WP system of the machine does not exist this problem. Of course, there's no problem with Android's 2G-capacity phone. Control the number of background programs in addition to manually "off the process", but also to prevent some programs automatically opened in the background, it is necessary to use some third-party software to control the boot-up items, usually this type of software needs to get root permissions.

Rom

Rom is what we say the storage space, the common capacity of 4G, 8G, 16G, 32G, 64G and so on. ROM also involves a capacity problem, also divided into nominal capacity, actual capacity and usable capacity of three kinds. The nominal capacity is the above mentioned capacity. Rom actual capacity is much smaller than the nominal capacity, this is because ROM is divided into three parts, part of the system, which we usually "brush" the part of the brush, and the other part of the system software installation, for example, some phones will be separated 2G for the installation of software, and the rest is the user-controlled part, as " Internal memory card ". The function of the internal memory card is the same as the TF card we inserted, so we can copy the content we want at random. Of course, the function of the internal memory card is not exactly the same as the TF card, because some software packets normally can only be placed on the internal memory card, and the TF card can not be stored as the location of the packet, so it explains why the user inserted into the mass memory card after the installation of software is still insufficient space.

the difference between a flash card and a memory card, as well as Rom with Ram What are the differences?

The so-called "flash memory" is the flash memory is a non-volatile memory, that is, in the absence of electricity can also keep the contents of storage. Essentially a ROM (the concept of ROM is said below)
Then the general so-called computer memory, is RAM, is random access to memory, that is, randomaccess memory. is the random access, given an address can directly access the contents of the address unit, relative to the sequence of memory such as tape, and direct memory, such as hard disk (mainly refers to the mechanical hard disk, its access to the storage unit when the disc rotation and head movement, it is not "random access"). Computer memory is volatile memory, that is, the content will be emptied after power-down, modern computer memory is mainly DRAM, that is, dynamic random access memory, need to be timed refresh, that is, every several milliseconds need to re-"fixed" the data, otherwise it will be lost, but with low cost, high integration, Low power consumption (compared to SRAM (static random access memory)).
On the phone, sometimes the body built-in flash memory is also called RAM, but its and computer memory (RAM) is two concepts, not to be confused.
The following is a ROM, which is read onlymemory, which reads only memory. It is read-only during normal operation, is not writable, and can be saved after power-down. But ROM is not all "read-only", there is now programmable read-only memory, some can only write once is the P (Programmable) ROM, as well as Erasable Rom, called E (erasable) PROM, need to be wiped with ultraviolet, as well as the electric wipe E ( Electrolic) EPROM, as well as FPGA (Field Programmable gate array), are class programming ROM. In other words, although it is read only, ROM can also write things.
Similarly, flash memory (flashmemory) is also a type of ROM, but we use it as a storage medium.
It is because of the read-only nature of the ROM and the nature of the power-down that it does not disappear that it is often used to store programs that do not require frequent changes, such as the system "firmware", which is why phone firmware is often called ROM.

TF card SD card CF card and other mobile phone memory card What is the difference? Which is better?

Now the main memory card type is many, mainly have small flash card (cf card-compactflash), smart card (SM Card-smart media) and Memory Stick (MS Card-memory Stick), xd image card, and Multimedia Card (MMC card- MultiMediaCard) and a Secure digital card (SD card-securedigital). Let's introduce each of the following:

1.CF Card

CF Card is the first to launch the memory card, but also everyone is more favored memory card. CF card is popular for many reasons, one of the more important is cheap. Compared to other digital memory cards, CF card unit capacity of the storage cost is almost the lowest, the speed is relatively fast, and large capacity CF card is easier to buy.

We can contact the CF card into CF type I/cftype II two types. Since the slots of the CF memory card can be backwards compatible, the TYPEII slot allows the CF TYPEII card and the CF Type I card to be used, while the type I slot can only use the CF Type I card, but not the CF Type II card, friends in the purchase and use must pay attention to.

2.SD Card

The small size of SD card, widely used in digital camera, is a brand-new memory card product developed by Panasonic, Toshiba and SanDisk Company in Japan, the biggest feature is to ensure the security and secrecy of data information through encryption function. The SD card is in the same shape as the MultiMediaCard card and is compatible with the MMC Card interface specification. Note, however, that in some products such as mobile phones, SD cards and MMS cards are not compatible. The SD card is priced higher than the same capacity MultiMediaCard card.

3.MS Card

5 years ago, Sony produced its own flash memory card, the Memory Stick-memorystick. It is used in digital devices such as Sony's digital products, handheld computers, MP3, digital cameras, digital cameras and so on. The MemoryStick Pro and MemoryStick duo, derived from MemoryStick, are also the product of the high volume and small volume development of Sony memory sticks.

4.SM Card

The SM card was first introduced by Toshiba, which simply encapsulates the memory chip and does not contain a control circuit, and all read and write operations are safely dependent on the device that uses it. Although the structure is simple can be done very thin, in terms of portability than CF card, but the poor compatibility is its deadly injury, a SM card once used in the MP3 player, the digital camera may not be able to read and write. Its market performance has been resonant, and there will be no more new devices to support it.

5.MMC Card

The MMC card was launched by SanDisk and Siemens in 1997, and it popularized a bit of SD card light. Later, the SD card standard retained the compatibility of the device to the MMC card, that is, although the device using the MMC card can not use the SD card, while the use of the SD card device is able to use the MMC card, in some cases makes MMC a good substitute for SD card. The size of the MMC card is basically the same as SD, which is thinner than the SD card, but it is still strong in reading speed. So the price is also more inexpensive MMC.

Different brands of mobile phone manufacturers in mobile phone production process, hardware facilities are also very different, If the phone memory card slot size specifications are different. And the memory card manufacturers also produce different sizes of mobile phone memory card, to match the different sizes of memory card slots for the use of mobile phones. And name these memory cards (such as TF cards, MMC cards) to differentiate these different sizes of memory cards.

The general said that these cards are not the same size specifications, so there are so many names (the process is a little bit different).

TF Card (full name trans Flash, also called Micro SD card, pluggable SD card converter becomes SD card use, Motorola mobile phone is more commonly used this memory card)

MINISD Card (can also be inserted after SD adapter when using SD card)

SD Card (full name is Secure Digital Memory card, also used for digital camera/mobile phone and other digital products)

RS-MMC Card (also called Mobile MMC card, pluggable MMC card adapter when MMC card used, Nokia mobile phone with more)

MMC card (full name multimedia card, also used for digital camera/mobile phone and other digital products

The difference between cell phone memory and computer memory

The function of memory is to temporarily store the operational data in the CPU and exchange data with external memory such as the hard disk. Computer memory is because the hard disk reading speed is too slow, so it is the role of the transfer. If the memory is too small, the computer will lag, and the more programs run, the more obvious. Phone memory includes "rom+ram+ memory card" Three parts, only the RAM is equivalent to the memory of the computer, and the mobile phone brush is actually the brush ROM.

Phone memory and computer memory

Usually manufacturers confuse the phone memory with the memory card, its nominal "memory" is often wrong refers to the SD card or other peripheral storage space, the role and the computer's hard disk.

In essence, the phone memory includes "rom+ram+ memory card" Three parts, only the storage RAM is equivalent to the computer's memory, and the rom+ memory card (usually an electric wipe except writable read-only memory EEPROM) equivalent to the computer's hard disk.

Rom is not enough, can be through SD expansion card (memory card) is to increase the phone storage space, equivalent to the computer to add external hard disk. The phone cannot expand memory (RAM) capacity by adding a memory bar like a computer.

Cell phone memory is the same as the nature of the media, is the permanent storage of data, even if the shutdown is also stored, and the computer's memory is used to store the system is currently running programs, is volatile memory in the power outage after the data will be lost, temporary storage data, shutdown is cleared, the computer permanently stored data is the hard disk.

Phone storage = Body memory (Rom+ram) + memory card
In fact, it is a confusing concept that the manufacturer defines the external storage space as memory, which is defined by the "storage space inside the phone". For example, mobile phone 4G memory has at least three kinds of statements: 4G of external storage space, 4G of RAM, 4G Rom+ram and so on.
Mobile ROM is the operating system and software installation, ROM is too small to install a lot of software, RAM is the program running memory, if the ram is too small to run many programs at the same time, or some programs can not run directly, and the external storage space is where you put the picture Video music, is also your mobile phone even after the computer can see the U disk, this place is too small to put a lot of things.

Mobile phone storage consists of two parts: the internal memory of the mobile phone and the external storage "memory card", and the body memory including ROM and RAM, only the RAM is the real memory, mobile phone operating system is in the form of firmware in ROM, mobile phone brush is actually brush ROM, a good proportion of the system. As the common Android phone configuration, "The body memory capacity of 1GBROM+256MB RAM, equipped with a microSD (TF) card, the maximum expansion capacity of 32gb". "
In the PPC mobile phone, the operating system is also cured in ROM, and the RAM is divided into storage and program two parts, storage is used to store the installation software, program is used to load the operating system and running software.

Running memory and physical memory

The memory of the smartphone runs memory Ram (System memory) and physical memory rom (non-running memory) for two minutes.
The ① phone runs on memory equivalent to the memory of the computer, RAM (random access memory randomaccess memories), and the larger the RAM, the more programs and fluency the phone can run. "out of memory" errors are prompted when there is insufficient RAM.
② Mobile phone's non-running memory, equivalent to the computer hard disk system partition, namely ROM (read-onlymemory), the larger the ROM, like the larger the disk, can store more data.
Once the previous ROM has been shipped, the data stored above cannot be overwritten or deleted, and the data will not be lost due to power loss. Later, a new type of EEPROM (electronic can erase programmable read-only memory) instead of the original ROM. Later, flashmemory (Flash) instead of EEPROM, flash memory can easily be rewritten. Now we say that the ROM in the smartphone generally refers to flash Memory (nor type).
In Android phones, some of the ROM is installed operating system (firmware package), it is possible to pre-installed a lot of programs, like Windows system disk, which is protected, for ordinary user ROM is read-only, only to obtain the highest operating system permissions (Root) to write data to it, That is what we call the Brush ROM package. Another part of the ROM space is allocated to the user to store the data, which is still called "read-only", but has been completely divorced from the "read-only memory", known as "phone internal storage" or "body memory", as opposed to external storage "memory card".

Usually in the installation of the program, will be prompted to be installed in the mobile phone storage and memory card. Try to put large files in the memory card, because the phone storage to reserve some space to do the cache, too full will affect the operation of mobile phone system, like computer system C disk.

Running memory (System memory)

Mobile phones often prompt for insufficient memory, in fact, the system is out of memory.

The running memory of the mobile phone (referred to as the storage) refers to its own memory, not including the capacity of memory card, mobile phone operation determines the speed and processing strength.

Phone system memory is typically viewed using software such as process management.

Just when the phone system memory is the largest, after boot call butler, firewall, automatic lock keyboard and other software automatically run and resident memory.

Try not to install other font files, font files will be loaded into memory, and the font capacity is large, will occupy a lot of memory.

Enter airplane mode (airplane mode or offline mode) so that communication-related threads are turned off for greater system memory. This is only used when there are special needs, such as the need to play a very high system memory requirements of the game.

There's one more trick.

Typically, the unit that measures the phone's memory space is MB, or MByte. But now some handset manufacturers begin to introduce their products with Mbit. Because 8bit=1byte, so 8mbit=1mbyte. If a memory only 50MB products, swap with Mbit to do units, then it can be written as 400Mbit.

What is the difference between a phone's own memory and a phone card?