I hear people often talk about memory and hard disks and the like, I don t understand, I solve! Deta

Disk cache refers to a region of memory allocated by the operating system in normal physical memory for disk input and output.

Disk cache is divided into read cache and write cache.

Read caching is when the operating system keeps the read file data in the memory space (this memory space is called the "memory pool") when the memory is free, so that the next time the software or user reads the same file again, it does not have to be read again from the disk, thus increasing the speed.

Write caching is actually the data to be written to disk is stored in the memory space allocated by the system for write cache, and when the data saved to the memory pool reaches a certain level, the data is saved to the hard disk. This reduces the actual disk operations, effectively protects the disk from damage caused by repeated read and write operations, and reduces the time required to write.

Depending on the writing method, there are two types: write-through and write-back. When reading the data from the hard disk, the system first checks the request instruction to see if the data you want is in the cache, and if so, the cache sends the response data, which is called a hit. This eliminates the need for the system to access the data on the hard drive, and since SDRAM is much faster than magnetic media, data transfer is accelerated.

Write-back is to find in the cache when writing hard disk data, if you find it, the cache will write the data to the disk, most of the current hard disks are using write-back cache, which greatly improves performance.

Cache is also a type of memory, and its data exchange speed is fast and the operation frequency is high.

The buffer of the hard disk.

The buffer of the hard disk is where the hard disk exchanges data with the external bus. The process of reading data from the hard disk is to convert the magnetic signal into an electrical signal, fill and empty it again and again through the buffer, refill it, and then empty it, and send it out step by step according to the cycle of the PCI bus. It also works to improve performance, but it differs from caching in the following ways:

First, it is hardware with a fixed capacity, unlike cache, which can be dynamically allocated in memory by the operating system. Second, its impact on performance greatly exceeds the performance impact of disk caching, because without buffers, it would require a disk to be read or written once for every word passed (usually 4 bytes).

current

controlset\control\session manager\memory management\iopagelocklimit

This means modifying the page cache.

It's useless, the memory is as big as it is, 128m is 128m 512m is 512m

Because you don't know how much memory the current file is requesting, i.e., the amount of address space that is cached in memory, unless you know how much memory the application has requested during that time period, and the value will vary depending on what you do.

64m: 1000;

128m: 4000;

256m: 10000;

512m or greater: 40000

I didn't get it. Maybe it's to change the size of the page file, there's an egg.

The location of the disk cache file is inside the temp

The quality of TB and 2TB hard disks is passable. Of course, electronic products have a certain probability of failure, so pay attention to the warranty duration when purchasing, the warranty of hard disks is generally 2 years or 3 years, try to choose a 3-year warranty.

2. Try to choose 1TB7200 to 64MB cache for system disk, and 2TB is generally used as a warehouse disk.

3. At present, there seems to be no single-disk 2TB hard disk sold on the market.

4. You can buy it anywhere. If you buy it in the computer city, you can use the barcode software on your mobile phone to check the authenticity. The things sold by several large online shopping companies can basically be guaranteed**, but it should be noted that they have direct products and consignment goods, so try to choose direct products.

There is no single disc 2T, only a single disc 1T, which is not bad for the money to use the Seagate 2T monitoring disk.

1. There is not much difference.

2. Not too clear.

The advantage is that the data is more secure or stored (read) faster, and the disadvantage is that it is possible to destroy all the data after one break.

The most basic ones are two modes, RAID0 and RAID1. All require at least two hard disks to achieve this.

If you think of each hard drive as a bucket.

raid0 is equivalent to pouring half a bottle of water into each bucket at the same time, which adds up to just one bottle in the bucket, but it only takes half the time. When taking a bottle of water from a bucket, it also takes half a bottle from each bucket at the same time, which is theoretically only half the time it takes to take only one bottle of water from a bucket.

The advantage is that if one of the buckets is broken, the water stored in the other bucket will also be unable to fill or take water because it cannot meet the water intake method mentioned above.

If you think of each hard drive as a piece of paper.

raid1 is to write a sentence on a piece of paper, and will write this sentence on each paper at the same time, so that if one piece of paper is broken, the sentence on the other paper is still there, and it can still be used. The disadvantage of this is that if you buy two pieces of paper that can write ten sentences, you can only write ten sentences instead of twenty sentences in total, because you have to copy them once.

Disk array is a technology that controls the interconnection of multiple hard disks by a hard disk controller, so that the reads and writes of multiple hard disks are synchronized, reducing errors, and increasing efficiency and reliability.

Actually, it's not necessary.

1. What is the difference between SATA2 and SATA3 interface hard drives? - Answer: The speed is different, SATA3 is faster, but it is no different on HDD, because the current HDD is far from the speed of SATA2.

2. Can laptop hard disks with different serial ports be connected to desktops with different serial ports for use? ——

1: The transmission speed is different, 2 supports 3G S and 3 supports 6G: SATA2 and SATA3 interfaces are the same and compatible with each other, but the speed can only be calculated as low.

It can be connected to the desktop for use, but the desktop hard disk rack is large, and the general notebook hard disk should be fixed with a hard disk case, 3: The most important attribute of the mobile hard disk is the storage speed, which must be the hard disk box and the hard disk core speed of 7200 The transfer interface is sata3 is good, Hitachi and Western Digital black disks are recommended.