SCSI refers to the small computer interface method. Ordinary computers only need to add a PCI SCSI card to connect the SCSI disk at will. If you want to use the SCSI disk for C drive boot, you only need to install it in the host computer. Just set the first boot to SCSI in the CMOS settings. There are no special requirements for hosting and other peripherals. It does not affect the simultaneous use of other IDE devices. A dual-pass SCSI card can connect up to 30 disks of the same speed, and a single-pass 160 SCSI card can connect 15 disks of the same speed. They do not affect the speed of each other and only occupy one IRQ. Comparing with ordinary IDE hard drives, summarize some advantages:
1. SCSI can support multiple devices, SCSI-2 (Fast SCSI) can connect up to 7 SCSI devices, and the dual-pass of ULTRA2 and ULTRA3 can connect 30 SCSI device. Single pass to 15 disks. In other words, all devices only need to occupy one IRQ. At the same time, SCSI also supports a wide range of devices, such as CD-ROM, DVD, CDR, hard disk, tape drive, scanner, etc.
2.SCSI also allows another device to search for data while transmitting data to one device. This can achieve higher performance in multi-tasking operating systems such as Linux and Windows NT.
3. SCSI takes up very little CPU and indeed has obvious advantages in multi-tasking systems. Since the SCSI card itself has a CPU, it can handle the affairs of all SCSI devices. When working, the host CPU only needs to send work instructions to the SCSI card, and the SCSI card will work on its own. After the work is completed, the work results will be returned to the CPU. During the entire process , the CPU can perform its own work.
4. SCSI devices are also intelligent, and the SCSI card can queue CPU instructions by itself, thus improving work efficiency. When multi-tasking, the hard disk will complete adjacent tasks at the current head position and then process them one by one.
5. The fastest SCSI bus now has a bandwidth of 320MB/s, which requires the use of a 64-bit 66MHz (166MHZ) PCI slot, but the maximum speed that can be achieved in an ordinary PC is 133MB/s,
(The above points 1-5 are reposted, I have made some modifications where the other party made mistakes)
6. Nowadays, the single disk speed test of high-end SCSI disks and 10K/15K is close to or exceeds the RAIDO method of two 7200 rpm mainstream IDE hard disks. However, SCSI disks are also divided into grades. Generally, the newer the model, the faster it is, and the noise and temperature are better controlled. For example, the Leopard series made by SEAGATE is divided into generations, including Leopard 1-7 generations. The mantissa of the model represents the generation. For example, ST318705LC represents Leopard 5 generations 18G, C represents 80-pin server hot plug, and if it ends with W, it represents 68 pins. The same goes for the latest 15,000-rpm STX15 models. For example, ST336752LW represents the 36G X15 2nd generation. Leopard's previous disk was a Barracuda series 7200 rpm SCSI disk. SCSI hard drives made by FUJITSU are famous for being fast, quiet and cool. The appearance is gentler and more approachable than SEAGATE, which is in line with her characteristics. Mainstream models are distinguished by the order of the last digit of English letters, which is slightly different from SEAGATE. MAN318MC represents MAN18G 80-pin, and if it is MAN318MP, it represents 18G 68-pin. First there is MAH, then MAJ, then MAN, and finally MAM. MAN and MAM are the latest high-end disks, equipped with 8MB buffer, of which MAM is 15K RPM, which is equivalent to X15II.
7. Newer SCSI hard disks only have two interface methods - 68-pin and 80-pin (older disks have 50-pin interfaces, as those who played SCSI in the early days know this best, and some friends are still using it). The 80-pin design principle is directly provided to the hot-swappable module of the server and supports hot-swappable plugging. The 68-pin pin is for ordinary PC users and does not support direct hot plugging. The 80-pin disk can also be used on ordinary desktop computers (this is how I use and promote it). You only need to add an 80 to 68 LVD adapter. It is not needed if there is an occasional power outage or accidental hot-plugging. Worry. The adapter must be of good quality, otherwise even the U160 disk will become 40MB. Of course, quality and price are directly proportional. There are also ordinary adapters, which are 40MB in SE mode. In appearance, there is not much difference between the ordinary SE adapter and the LVD adapter. The only reliable way is to connect it to the disk and use it. There are two judgment indicators. One is to look at the display. Speed, the second is to look at the test data. Some people worry that the speed will be affected by the transfer, but the actual test results are the same.
8. SCSI and IDE are a little more complicated to set up. If more than 2 disks are connected to a channel, IDs need to be assigned, just like several brothers queuing up. Otherwise, none of the disks will be recognized. The jumper method for the 80-pin disk is performed on the adapter. The 68-pin disk is connected to the jumper on the hard disk body. If you only connect one hard drive. There is no need for jumpers. IDO is the bootable disk by default, and other IDs are non-bootable disks.
The SCSI channel occupies an ID7 by default. SCSI channels will be automatically terminated and can be used stably without additional termination. However, it is safe and reliable to provide a termination signal at the end of the SCSI disk, so high-end LVD cables have multiple ends and are equipped with terminators at the end, which are divided into fixed terminators and movable terminators.
9. The so-called LVD refers to the low voltage transmission method, because to achieve the theoretical speed of 80/160, it must be the LVD method. It is written in English: Low Voltage Differential. LVD is divided into 80MB and 160MB. LVD uses 2 signal lines as a group for signal transmission, one of which is at high potential and the other at low potential. If you want the party receiving the signal to recognize the change in potential, you must apply high and low voltages to the two lines respectively. This method can offset the interference parts and maintain normal data transmission when both parties are interfered with. It also expands the identifiable critical range of the signal. However, the premise for the LVD method to work is that the distance between the two lines and the interference source must be equal, so the two signal lines must be bundled together (just like the twisted pairs used in LAN). The real flat wire for LVD should be twisted pair. As for some U160 flat wires, it is purely for the purpose of cost saving. After using it, although it may work normally, the wiring length of 25m will not be guaranteed.
10. The difference between dual U160LVD channel SCSI and single U160LVD channel SCSI: dual 160 is two 160 parallel channels, each channel can connect 1-15 U160 disks, while the single U160 card has one U160 channel and the other is a 40MB channel. The two cards are not of the same grade. Generally, dual-pass cards are much more expensive than single-pass cards.
11. Having said so much, it seems complicated. In fact, simply speaking, you need to use LVD SCSI card + LVD SCSI disk + LVD cable to form your ideal fast, stable and durable SCSI system, especially for audio and video. People and non-editors must use SCSI disks to ensure that frames are not lost. Using an IDE to do NLE is painful or even impossible.
12. So what are the outstanding benefits that ordinary players can feel when using SCSI?
A. When moving and copying data, you can obviously feel that it responds faster than the IDE. For example: copying a 460MB file to a SCSI disk only takes about 10 seconds.
B. We all know that the C drive used in the system has frequent data searches, reading and writing, resulting in fragmentation and discontinuous space. Practice shows that if the IDE disk is used in the system for a long time (for example, if the fragmentation and space are not defragmented for a month), the system will obviously feel uncomfortable. The response time becomes slower, and this feeling is almost no longer the case after SCSI is used as the system disk!
C. You can do many things at the same time. Have you ever tried listening to MP3 and playing Q3/CS at the same time, while 2 or 3 copy windows and several IE windows are still open in the background? The more obvious feeling is that when copying large files between partitions, the advantages and speed of SCSI are fully demonstrated.
D. However, it should be noted that if you compare the advantages and disadvantages of SCSI and IDE purely in terms of the time it takes to install the system or the time it takes to start the system, the results you will get will disappoint you, because SCSI is often better than the 7200 rpm IDE disk. Clicking will be a little slower, unless it is the latest 15K disk. Those who only focus on these 2 points are advised not to buy SCSI. Our approach is generally to use a SCSI disk as the system and an IDE as the backup disk. Of course, no one will blame you if you have more money and abandon IDE disks. Although SCSI is much more expensive than IDE, it is worth the money and is especially suitable for heavy-duty work situations, such as Internet cafes. What's more, only about half of the new second-hand SCSI equipment is licensed. hehe.
13. When buying SCSI disks, pay attention to distinguishing between old-model thick disks and old-model thin disks. The cheap price of these disks often makes you tempted. Even the thin pan will let you down. Some of the obsolete disks are thick disks, which are equivalent to two IDEs stacked together. Although some have U160 interfaces and 4MB cache, don't expect them to be very fast. Especially the noise. I have seen IBM's U160 thick disk, and I was shocked even though I was mentally prepared. The noise is probably louder or quieter than the American Longbow Aberdeen combat helicopter. The entire desktop was shaking. Fortunately, the price was cheap. He only sold the 36G model for 360 yuan. When it comes to noise, FUJITSU is the leader in this area! The working noise of his MAJ/MAN/MAM series is the same as that of a quiet IDE hard drive. Many times I can't tell whether it is the sound of the IDE or the sound of the SCSI disk. New SCSI hard drives are the same size and thickness as IDE hard drives, but the difference is that SCSI looks more dazzling! The circuit board is unmatched by IDE, with additional cache chips, CPU, a large number of high-end power supplies, etc. Secondly, there is the consideration of brand. There are not many SCSI manufacturers. Over time, a mental set of the advantages and disadvantages of SCSI has been formed. Seagate, Fujitsu, Quantum, and Hitachi are the major manufacturers, and the server SCSI disks of other brands such as HP, Compaq, and Dell are mostly their OEM disks. Among them, Seagate and Fujitsu have the most, and they are the bosses.
IBM makes its own SCSI disks. The typical representative is the ULTRA STAR DDYS series. Its performance and temperature and noise control are not as good as those of the SCSI disks, and the disk failure rate is also relatively high.
The above summary is purely personal experience and experience. If there is something wrong, please tell me and discuss with each other. My purpose is to "popularize the superior SCSI to ordinary people's homes~! Everyone can feel the charm of SCSI" ^^
One dual-pass 160 card+ The four ESERVER Leopards 18G are in working condition. They contain other PCI devices including sound cards, graphics cards, etc., as well as a 30G IDE hard drive. The host used is just a VIA KT133A host with on-chip SD memory. But such a SCSI system is 2 times better than using P4.
4GA + two 7200 rpm IDE RAIDO modes are still powerful!
Essential knowledge and driver downloads for installing SCSI: [Recommended]
Special reminder at the beginning: Ordinary users are strictly prohibited from using the FORMAT function that comes with the BIOS of the SCSI card itself. With low-level formatting, more than 99% of SCSI disks cannot be recovered after use! Don’t! Remember!
A. After plugging in the card and connecting the disk for the first time, there should be BIOS detection information of the SCSI card and a prompt for BIOS setting shortcut keys when booting. Generally, there is no need to enter the BIOS settings. The default one is the best. Unless you want to use the SCSI VERIFY function to detect whether the hard disk has physical bad sectors.
B. After detecting and searching for 15 IDs (if it is a dual-channel card, it will search for 15 IDs of 2 channels in succession. ), can correctly identify the disk model, capacity, synchronization rate, and bandwidth mode.
C. Before setting up a SCSI system for the first time, our approach is generally to connect the card and disk first, and then enter the previous For old systems, the recommended system is WINDOWS 2000/XP. After finding the card driver in 2K/XP, use the disk manager to partition and quickly format. (WIN2K has a powerful disk manager, located at: " Right-click on My Computer----->Manage----->Disk Management.
Special Tip: Many friends have reported that they cannot find the newly installed SCSI disk in the system. In fact, the reason is very simple. It is not that the disk is broken, nor that the system does not recognize the disk. It is because the system needs to be signed and marked by the disk before it can be displayed in the resource manager. These must be done in the disk management. < /p>
D. If you want to use SCSI for system startup, remember to activate the C area of ??the startup disk after using the disk manager of 2K/XP to quickly partition and format it. This principle is the same as that of DOS Same as the FDISK under, SET ACTIVE is required.
E. In addition to ADAPTEC products, other SCSI cards such as LSI53C1010 INITIO or QLOGIC need to press F6 after the first restart when installing 2K or XP. Press the key and follow the prompts to insert the pre-made SCSI driver floppy disk. Otherwise, a full screen of blue screen prompts will appear: Inaccessible unknow harddrive...
F: If you bought a different model If you want to directly connect the SCSI system disk to the new card, you cannot directly unplug the old card and connect the new card. A blue screen will appear. 2K/XP system will CRASH unless you reinstall the system. The easiest way is, If the old card does not work in the old system, insert the new card into the system, wait until the system recognizes the driver of the new SCSI card, then shut down the computer, connect the SCSI cable to the new card, and unplug the old SCSI card so that you do not need to re-install it. I installed the system and upgraded to a new SCSI card!
Here are the download links for several major SCSI drivers that I sell:
A. Jianbang TERAM DC390U3D LSI53C1010-33 dual-channel 160 card/LSI895U3/LSI53C1010-66:
hdd.com/down_view.asp?id=53