what is a scsi drive how it is made primary and secondary?

Question

need to know the functions of a scsi and recomend which is best among SCSI SATA and IDE

Answer 1

Hi there.
I do not know what you mean by " GIVEN F6".
SCSI has nothing to do with Master and Slave. ( these are IDE/ATA only. )
I am surprised that you detected one of them, since it would be
pure luck that you got it going.
DETECTING the drive is only the first step, and you leave out a LOT of details that would help to answer your question.

If you 'detected' one SCSI, then I will assume you plugged in the SCSI controller card properly, or have it onboard, and enabled. I will assume that you plugged in the SCSI, 50 pin cable correctly from the SCSI card/connector, to the 50 pin, INTERNAL SCSI drive. ( there are 25 pin SCSI, 50 pin SCSI, 68 pin SCSI, and other proprietary SCSI cables and pinouts such as used on SUN computers and mainframes )

There are not 2 drives with SCSI, ( not master and slave ), but 7 drives, or 15 drives, with Ultra, Wide, SCSI II, etc., which is what I use.
SCSI started with 8 devices ( later 16 ). All devices, including the controller chip/ card, must have an ID number assigned from 0 through 7 ( or now, 0 through 15 ). The highest number gets servicing FIRST, so that the normal practice is to set the controller card/chip, to 7. This leaves 0 through 6 free for 7 harddrives. You cannot have two SCSI devices with the same ID number. The LAST device in a long chain of SCSI devices must be terminated, either with a termination ( internal electronically activated ) switch on the device, or with a mechanically inserted row of resistors, or with a dongle that plugs into the last port, or ribbon cable connector, that has a series of resistors in it. Terminating the device at the end of the cable is normal, and is done on floppies and harddrives, -- you just don't manually do it anymore --- floppies had to be manually terminated in the beginning, but now use built in " average" termination values, that are always connected. Harddrives have terminating resistors built in. If a device does NOT have terminating resistors on the END of any cable, the signal, generated by the motherboard/controller card/ chip, races at high speed through the cable, and when it gets to the dead end of wire at the far end, it reflects, and bounces back down the cable, garbling up the signal. The terminating resistors absorb the signals at the end, dampening the reflected noise, so that the data seen by both the harddrive and the controller, is valid.
In practice, you " CAN " sometimes get away without having a terminator, if you are using very high quality equipment, on shorter lengths, with devices that have automatic sensing and termination circuitry. If you use just ONE device, on a short cable, and it is well designed, you can get away with no termination in some cases.

You obviously do not know about terminating the SCSI chain. Your FIRST installed drive may already be electronically JUMPERED with termination, or have a row of terminating resistor packs. ( both drives may be non-terminated, or BOTH could have terminations enabled - in these cases, putting two together will cause problems )

Go to the manufacturers website of both harddrives that you wish to install, and find the jumper pins for both terminations, and for DEVICE NUMBERs. You do not state your operating system. You do not state your drive manufacturer. You do not state whether the drives are internal or external. You do not state whether the controller is a CARD, or onboard. All these have different methods of resolving the conflicts, and setting up the jumpers.
One method of getting the SECOND added device to work is to remove the first device, and just install the second one alone. If there is a TERMINATION, or SCSI ID conflict, just putting in the second device alone, may allow your system to see it. If so, go into the DEVICE MANAGER, and determine the SCSI ID of the drive. Do this with the first drive. If they are the SAME, you must change one of them. In the DEVICE MANAGER, check to see what the SCSI controller ID is - again, you can not jumper a harddrive to this number. If your controller card, or onboard SCSI chip are the OLD, 8 device type, and one or both of your SCSI harddrives that you are trying to add are the newer, 16 device types, you can have conflicts on the SCSI IDs of the harddrives being out of range, say for example, the drive is set for SCSI ID 13, but your controller only goes to 6, and the second harddrive you are trying to add is set at SCSI ID 14, then you could run into problems. Again, without knowing what the controller chip/card is, nor knowing what the harddrives are, I can't help you.
THEN... once you know that the controller, the first drive, and the second drive all have different SCSI ID numbers, then, you have to determine WHICH of the 3 are terminated. The controller should be terminated at one end, and the farthest harddrive on the other end must be terminated. Again, if the drives are internal, the termination would be on the manufacturers website. If the drives are external, the box containing the drives would either have a terminate switch, or, 2 SCSI connectors, and you have to put a SCSI terminator plug ( dongle) in one of the two.
The middle box or harddrive should NOT be terminated, since this will deaden the signals too much, and you will run into communication problems.

Then, once the system detects that there are SCSI drives, you have to worry about FORMATTING the SCSI devices, and I am hoping you are using XP, since win 95 or win 98 will
require you to use specific SCSI formatting software to format factory zeroed drives. Most of the SCSI drives I run into do NOT have Windows " FAT " partitions on them, and although " detected", they are not usable by any Windows Operating System. You don't state WHAT is "detecting" the first harddrive, so I cannot help you set up the drive.

I notice that you asked this question twice, and only got one 'answer' that gave you NO information on SCSI at all, which demonstrates that you are using a technology that few " PC " users understand. I have been using SCSI for a LONG time, and am surprised to see you using it! APPLE MACS used SCSI for many years, since it was vastly superior to IDE, but was also more expensive. Serial ATA is now almost as fast ( although the latest, fastest, SCSI made, especially in high end RAID, still outperforms anything ), so that on most machines, SCSI is not used anymore.
As for your concern of whether the problem is a cable fault, or a jumper problem, since you don't know that there are 8 or 16 devices in SCSI, nor do you know about TERMINATION, I would guess that you have a JUMPER problem. Please see the manufacturers website. Do one drive at a time, before you try BOTH. Write down all the jumper and termination settings.
You should get both drives to " DETECT", but I do not have enough information to help you with actually formatting or using the " detected" drives ,,, ,,, There are 2 days left for you post additional information if you want to get detailed, accurate help, at the time I am writing this...
There was one more thought that occured to me - that high end onboard or ULTRA UDMA or IDE or ATA PCI cards will report themselves as SCSI device drivers in various WINDOWS operating systems, and that you do not have SCSI harddrives at all, but do not know that the new " SCSI" device controller is just the ordinary chipset now used for harddrives. If this were the case, the CONTROLLER of the harddrives would be listed under the SYSTEM, Device Manager, as SCSI, BUT, under this category, it would clearly state IDE/ATA/etc. ( not SCSI) AND, the harddrives listed above would clearly state the name and type ( NOT AS SCSI. ) Furthermore, the properties of the drives would NOT list the SCSI ID numbers nor would the TAB above list the SCSI PROPERTIES. If this is the case, there is only a Master and SLAVE harddrive, which can usually be connected as SINGLE, Master with Slave, Slave, or CS, Cable Select, in which you take your ribbon cable and CUT out a section of wire, and jumper both drives as CS. Again, you do not name the controller chip, nor the harddrive models, so that I can't help you with specifics until you post some meaningful data. Your question is coming to expirey, and you have received no actual SCSI information from the other two Answerers, who don't understand your question, and don't know anything about SCSI. You ask which is best, SCSI SATA harddrives, or SCSI IDE harddrives, neither of which exist. THE CONTROLLER of SATA and IDE may list "under" the SCSI CONTROLLER heading, but the drives it CONTROLS would just be the ordinary SATA, UDMA, IDE, ATA, type, not SCSI. Hope this clears up a few possibilities!
If you post some meaningful information before your question expires, you could still get some meaningful help..

good luck

robin

Answer 2

It really depends upon cost. SCSI is actually more for servers and redundant arrays. SCSI drives spin at higher RPM's meaning the disk access is faster; but they are more expensive and hard lower storage capacities. SATA is faster than IDE regardless of transmiting data serially. IDE is a technlogy that still exists but is being phased out.

The funny thing is that end users by all kinds of high end hardware to make their computers as fast as possible, but truthfully there is only a finite amount of difference you can notice.

Unless you are putting together a server or doing some highend graphics desing or programming, just get a SATA drive. Now you will need a mainboard that supports SATA or at least a controller card.