SATA (Serial ATA) hard disk

SATA (Serial ATA) hard disk, also known as serial hard disk, is the mainstream of computer mechanical hard disk, has basically replaced the traditional PATA hard disk. SATA's full name is Serial Advanced Technology Attachment. The Serial ATA Committee composed of Intel, APT, Dell, IBM, Seagate and Maxtor formally established the Serial ATA 1.0 specification. In 2002, Although Serial ATA related devices are not yet officially available, the Serial ATA Committee has already established the Serial ATA 2.0 specification. Serial ATA adopts serial connection mode, and serial ATA bus uses embedded clock signal, which has stronger error correction ability. Compared with the past, the biggest difference is that it can check transmitted instructions (not only data), and automatically correct if errors are found, which greatly improves the reliability of data transmission. The serial interface also has the advantages of simple structure and hot swap support.
intro

SATA, Serial ATA (Serial ATA), full name of Serial Advanced Technology Attachment, is a new hard disk interface specification jointly proposed by Intel, IBM, Maxtor and Seagate. Because of the serial connection, the hard disk that uses the SATA interface is also called the serial disk. The SATA specification increases the external transfer rate of the hard drive to a theoretical value of 150MB/s, which is 50% higher than Ultra ATA/100 and about 13% higher than Ultra ATA/133. The SATAII interface is scalable to 2X (300MB/s) and 4X(600MB/s). The difference between SATA150 and SATAII is mainly the speed of data transmission. Future SATA will allow the hard disk to overclock by increasing the clock rate, which can completely solve the data transmission bottleneck of the hard disk interface. The SATA hard drive interface requires support from newer motherboard Southbridge chips, such as Intel ICH6, Intel ICH7, nVIDIA nForce4, VIAVT8237, and Si S964. Advantages of SATA: Support for hot swap, fast transfer speed, high execution efficiency. 

Constitution and agreement

Each SATA disk storage node consists of a memory control interface MCI and a SATA disk controller, as shown in Figure 1. Among them, MCI is responsible for generating, encapsulating or decapsulating message packets according to message frame format, extracting and parsing operation commands for accessing storage nodes according to received message packets, including initialization, setting power saving mode of storage nodes, sleep or wake up, read and write memory, etc.
The communication between SATA host and SATA device adopts SATA protocol, [2] which is divided into physical layer, link layer, transport layer and command layer according to functional SATA protocol. The protocol hierarchy is shown in Figure 2. Hosts and devices are physically connected through SATA interfaces at the physical layer and are virtually connected through messages at other layers. The physical layer is the basis of communication between the host and the device, which is mainly responsible for sending and receiving the code stream, converting the high-speed serial differential signal into parallel data, and converting the parallel data into high-speed serial differential signal. The link layer is mainly responsible for error-free transmission of messages, including 8B10B codec, add-de-scrambling, CRC check, etc. The transport layer is mainly responsible for generating and analyzing Frame Information Structures (FIS). The command layer is responsible for generating and parsing operation commands for accessing SATA disks.
peculiarity

Traditional Parallel ATA uses a single-mode signal amplifying system called "single-end-signal-amplified-system". In this system, the noise will be transmitted and amplified along with the normal signal, and it is not easy to be suppressed; Especially serious at high speed, in order to effectively reduce the interference of noise, we have to use up to 5V voltage to transmit positive - normal signals, so that the normal signal of large voltage overtakes the noise signal of small voltage. Although the large voltage can effectively suppress the noise, the large voltage also indicates that the production cost of the drive circuit will rise, and the large voltage is more conducive to the design and manufacturing of high-speed transmission systems, and the transmission voltage of up to 5V limits the possibility of pursuing high-speed and low-cost.
Compared to Parallel ATA, the new SATA uses a differential signal-amplified system. This system effectively filters noise out of normal signals, and the good noise filtering capability allows SATA to operate at low voltages, requiring only 0.5V(500mv) peak-to-peak voltage compared to Parallel ATA's transmission voltage of up to 5V. "The more correct term is: peak-to-peak 'differential mode voltage'".
Compared to Parallel ATA's 5V drive voltage, the 0.5V SATA system saves power and its drive IC is cheaper to produce.
Technical index

BIOS Settings

Mainstream motherboards have full support for SATA hard drives, the following sections are described

1. The South bridge is the main board of the ICH5/ICH5R

Take Asus P4C800 as an example, this motherboard chipset is i865PE, and the south bridge is ICH5/ICH5R. After entering the BIOS, select the IDE Configuration Menu under Main, and two IDE operating modes can be selected under Onboard IDE Operate Mode: Compatible Mode and Enhanced Mode. Compatible Mode, which can be interpreted as mapping SATA hard drive ports to the corresponding Port of the parallel IDE channel, when you select this mode there are three options in the IDE Port Settings below:
Primary P-ATA+S-ATA: Parallel IDE drives occupy the Primary IDE Channel of IDE0+1, and serial SATA drives occupy the Secondary IDE Channel of IDE2+3. That is to say, the corresponding port of the second parallel IDE interface on the motherboard is unavailable.
Secondary P-ATA+S-ATA: Contrary to the above, the port corresponding to the first parallel IDE interface (Primary P-ATA) on the mainboard is unavailable because it is occupied by the SATA hard disk.
P-ATA Ports Only: indicates that serial SATA disk ports are masked and only parallel interface devices can be used.
Note: In the first two modes, the SATA1 interface on the motherboard automatically corresponds to the position of the master disk in the IDE channel, and the SATA2 interface automatically corresponds to the position of the slave disk in the IDE channel.
If Enhanced Mode is selected, the port Settings under Enhanced Mode change to Enhanced Mode Supports On, which also has three options:
P-ATA+S-ATA: Parallel and serial hard disk coexist mode, at this time SATA and PATA channels are independent of each other and do not interfere with each other, theoretically 4 P-ATA and 2 S-ATA can be connected to 6 devices at the same time, in fact, according to different motherboards, some south bridge chips only support 4 ATA devices. In this case, the SATA1 hard disk corresponds to the Third IDE Master disk and the SATA2 hard disk corresponds to the Fourth IDE Master disk.
S-ATA: Serial hard drive enhancement mode, at this time theoretically supports 4 serial hard drives, but it depends on the support of the motherboard (if it is an ICH5R chipset such as P4P800, want to set RAID mode, you must select this item, and set the Configure S-ATA as RAID item to Yes. Set the S-ATA BOOTROM item to Enable, and press Ctrl+I when the BIOS automatically detects the RAID.)
P-ATA: In fact, it is still a mapping mode, the SATA hard disk occupies the first IDE channel, the SATA1 port corresponds to the main disk of the first channel, and the SATA2 port corresponds to the slave disk of the first channel.
When you are using a traditional operating system such as Win98/Win NT/Win2000/MS-DOS, because they only support 4 IDE devices, please select Compatible Mode. Select the corresponding option in IDE Port Settings based on the actual number and location of your hard drives; When you are using newer operating systems such as WinXP/Win2003, you can select the Enhanced Mode to support more devices. Of course, if you install Win98+Win XP dual system, you have to choose Compatible Mode. In addition, some motherboard BIOS bugs, resulting in a single SATA hard disk installed on the Windows 98SE system can not be correctly installed SATA hard disk (such as: P4VT8), only need to upgrade the BIOS version to the latest version can be solved.
Note: Although the SATA hard disk itself does not have a master/slave, but if the port mapping mode is used, when you want parallel hard disks and serial hard disks to coexist, you still have to pay attention to the location of the hard disk do not conflict, and the boot order also needs to be adjusted in the BIOS according to the actual situation.
Taking GA-8KNXP Ultra as an example, briefly talk about the SATA Settings in the BIOS of the motherboard:
The chipset of this motherboard is i875P, and the south bridge is ICH5R. The setting options of the SATA part are in the Integrated Peripherals(integrated peripherals) under the Main menu. The setting functions are detailed in the following table (only the part about SATA hard disk Settings is listed) :
Boot device options are listed in Advanced BIOS Features, as shown in the following table:
From the above two examples, it can be seen that the motherboard of the ICH5/ICH5R south bridge is set to recognize SATA hard disks through two ways: port mapping and independent SATA channels. As to which mode and setting values should be selected, please refer to the above and determine the actual situation based on the number of S-ATA and P-ATA hard disks, the installed operating system, and which one is used as the system boot disk.

2. The South Bridge is the main board of VIA's VT8237

Compared to the ICH5/ICH5R chipset, the SATA setup part of the VT8237 is much simpler. Let's take the SL-KT600 series as an example. The SATA setting option is also in the Integrated Peripherals(integrated peripherals) under the Main menu:
Onboard PATA IDE(built-in parallel IDE interface Settings)
This setting allows users to configure the parallel IDE port features built into the motherboard.
Disabled: Disables the parallel IDE port function on the mainboard.
Enabled: Allows the use of parallel IDE port functionality (default).
Onboard IDES operate mode(built-in IDE preference Settings)
PATA is Pri IDE: Device priority on the PATA port (default).
SATA is Pri IDE: Devices on the SATA port are preferred.
Onboard SATA-IDE (SATA port on the mainboard)
Disabled: Disables the SATA port on the mainboard.
SATA: The SATA port on the mainboard is used as a common SATA port.
RAID: The SATA port on the mainboard can create a disk array (preset).
Here you only need to adjust the priority of the string and parallel ports according to the actual situation, and you can use the SATA hard disk normally. (As can be seen from the above options, the S-ATA hard disk can still be understood as being mapped to the P-ATA port.)
Note: The setup of the RAID also needs to be set up separately by pressing the "Tab" key to enter the BIOS setup screen of the VIA Technology RAID controller during startup. Please refer to the related manual.

Hard disk partition

Generally, after starting with Win98/Me startup program, FDISK, DM, PQ and other tools are used to partition the hard disk. So as long as the BIOS is set up correctly and can recognize the SATA hard disk after boot, the SATA hard disk partition is exactly the same as the traditional parallel port hard disk partition method.
If you use a boot CD such as Win2000/XP/2003 to start and partition, if your SATA hard disk cannot be recognized, Then you need to display "Press F6 if you need to install a third party SCSI or RAID driver... Press F6, load the driver with the floppy drive, and when the hard disk is correctly identified, it is exactly the same as the traditional parallel port hard disk partition method.

Operating system

1.Win98/Me
No matter what chipset is used, as long as the BIOS is set up correctly and the motherboard recognizes the S-ATA hard drive, it can be installed and used normally. (Note: Of course, it should be noted that systems such as Win98/Me can only support a maximum of 4 devices.)
2.Win2000/XP/2003 and other NT core systems
Here, because the ICH5 does not need to load RAID modules, it can be directly installed (in fact, the S-ATA is mapped to the P-ATA port, which is naturally the same as the parallel port hard disk). The ICH5R Southbridge controller is divided into two cases, one is to completely shield the RAID module in the BIOS, then it is the same as the ICH5, you can directly install; Second, if RAID is enabled (it is enabled by default in the BIOS), you need to press F6 to load the driver with the FDD during startup. The VT8237 should in theory be the same as the ICH5R, and most of its motherboard instructions also indicate that it does not need to load a driver when it is used only as an ordinary SATA hard drive (such as the SL-KT600-R of Shutek), but in practice, it is necessary to load a driver regardless of whether the RAID function is used. Due to the limited products I have contact with, I do not know whether this is the case, but also please readers to try.

Note: In addition to the S-ATA controller that comes with the Southbridge, other S-ATA controllers basically need additional drivers. Some motherboards support S-ATA and RAID controllers of third parties such as Promise in addition to the Southbridge itself. Please pay attention to the distinction.

Drive installation

After the operating system is installed, you need to install the corresponding drivers.
1. The ICH5 only needs to load the INF driver provided by Intel.
2. In addition to the INF driver, the ICH5R also loads the IAA3.0 or later driver.
3. The VT8237 requires the VIA Hyperion 4-IN-1 patch.
If you also use a parallel hard drive, it is best to use VIA IDE Miniport Driver, which is released independently by VIA, which is likely to reduce the burst transfer rate of the parallel hard drive, but has no effect on the performance of the serial hard drive.
Note: If you are using a third-party SATA control chip and RAID module, you will also need to add the appropriate drivers.
As can be seen from the above, the key to the use of S-ATA hard disk lies in the correct setting of the recognition mode in the BIOS, and because the BIOS menu of each motherboard manufacturer is different and the language of the motherboard manual is unclear, it has caused various problems in the use of S-ATA hard disk. Due to the different research and development capabilities, in order to let the motherboard manufacturers to unify this part, it is unrealistic at this stage, so the author only hopes that readers can refer to this article, according to their own actual situation to solve the problem.

Hard disk

As the external memory of personal computers and various servers, hard disk has played an important role in the storage field since its birth. The first hard disk in human history was produced by IBM in 1956 and had a capacity of only 5MB, which is almost the size of two refrigerators. Now a single disk can hold several terabytes, and the volume is only the size of a small box. Hard disk can be divided into mechanical hard disk and solid state hard disk, mechanical hard disk is a magnetic medium, solid state hard disk is a semiconductor storage medium, mechanical hard disk structure is complex by the head, platter, motor, etc., the internal structure of solid state hard disk is relatively simple, mainly by semiconductor flash memory chip packaging. Early hard disks are mechanical hard disks, its physical structure includes head, track, sector and cylinder, although there is no corresponding structure for solid state disks physically, but its interface protocol and mechanical hard disks are the same, in the description will also borrow cylinder, sector and other concepts. The magnetic head is the most expensive component of the hard disk, and it is also the most important and critical component of the hard disk. The traditional magnetic head is a combination of read and write electromagnetic induction head, hard disk read, write are two different operations, this two-in-one head in the design must take into account the read/write two characteristics, resulting in the limitations of hard disk design. In general, hard drives use MR heads (Magnetoresistive heads) with a separate head structure: the write head still uses the traditional magnetic induction head, and the read head uses the new MR Head, which is optimized for the different characteristics of the two in order to obtain the best read/write performance. In addition, the MR Head senses the signal amplitude through resistance changes rather than current changes, and the accuracy of reading data is correspondingly improved. And because the amplitude of the signal read is independent of the width of the track, the track can be made very narrow, thereby increasing the disc density.

When the disk rotates, if the head remains in a position, each head will draw a circular track on the surface of the disk, and these circular tracks are called tracks. Tracks are areas of magnetization on the disk surface that are magnetized in a special way, along which information on the disk is stored. Adjacent tracks are not close to each other, because when the magnetized units are too close together, the magnetism will affect each other, making it difficult for the magnetic head to read and write.
Each track on the disk is divided into a number of arcs, these arcs are the disk sectors, each sector can store 512 bytes of information, to read and write data to the disk, to the sector as a unit. That is, the minimum amount of read and write data is 512 bytes. [3]
A hard disk usually consists of an overlapping group of discs, each of which is divided into an equal number of tracks, numbered from "0" on the outer edge, and the tracks with the same number form a cylinder, called the cylinder of the disk. The number of cylinders on a disk is equal to the number of tracks on one side of a disk. Whether it is a double disk or a single disk, because each disk has its own head, the number of disk is equal to the total number of heads, so the total capacity of a hard disk is:
Storage capacity = Number of heads x number of tracks (cylinders) x number of sectors x number of bytes per sector (512B)