The Ultra ATA appear before, is be called the Fast ATA connect and can support the abrupt data of the 16.7 MBs/ s' deliver the rate only( note:Henceforth this text such as have no special elucidation, all point to connect a people's data to deliver the rate, namely the exterior delivers the rate), if to avoid the bottleneck that the sequence deliver( for example system leading, the big procedure load in, especially video frequency application), must raise to deliver the rate, to adapt the disk exaltation of the internal velocity.
Now, the whole industry has already accepted this standard of the Ultra ATA completely.The chip manufactory, include the main Intel of that market, and other ll hard drives produce the company, including the IBM, Maxtor, quantem( Quantum), seagate( the Seagate Technology) and western region data( the Western Digitial, WD) etc. declares to support this new agreement already.Along with the fireball ST series that the quantem releases to support the Ultra ATA after, the hard drive of Ultra ATA that comes from each factory grows profusely and quickly the sort at present the spirit of a thriving on the market.The hard drive capacity that enlarge continuously
Since the PC appear, the hardware and softwares always be placed in to promote mutually and mutually the antinomy of check and supervision is in the middle, and the most direct result that this kind of antinomy cause be, apply the software to ascend 100 trillions frequently, and operate system also the that day tend huge, from the DOS 6 of more than ten trillion arrive the 3. xes of Windows several 10,000,000,000,000, then arrive the Windows 95 of last 100 trillions, and along with change time, the document of DLL of those locust pests sort is also with the speed of the hard imagination to swallow your hard drive space, true some let person eliminate to can not stand.At the same time, hard drive also from more than ten trillions of the hour of the IBM AT, developped a few GBs of now, but the 16 GPs of Deskstar that IBM release last year are also an amount of sea that comes to a the 16.8 GBs.Although the hard drive enlarges continuously, the physical volume has no change, in other words, a capacity within hard drive is enlarging continuously, the diskette is less and less, the capacity have already become a kind of trend more and more and greatly.
To make hard drive of capacity enlarge continuously, read and write the improvement of the head and read and write to record the technical exaltation and should say is to rise decisive function:
The head magnetic resistance reads and write the way
The hard drive capacity promotes significantly and use of read and write the head to have the inseparable relation.Today, the hard drive of the high capacity almost uses the magnetic resistance head of the new generation to read and write the data.
The hard drive head makes use of the conversion of the magnetic field and electric field to record the data on the diskette.Head after hard drive the principal axis motor start after very short period of time, then would on the diskette with low-down fly highly.This kind of the motive for fly is in addition to coming from the principal axis motor's turn to move the buoyancy produce, the structure of the head has the very big relation with it also.
The traditional hard drive head is to read and write the unite as one type, also is to say in spite of is to write in or read to use the same of head.Therefore, the different characteristic that need to aim at to read and write does to correspond a ground of adjustment, this will sacrifice some functions and function by all means.But the magnetic resistance head contain two components, be responsible for the action that writes in and reads respectively, so can aim at their different characteristic to do excellent turn, to acquire the best access function.
1 the magnetic resistance head compare the breadth traditionally the respond type writes in the head, his width is equal to the width of the way of ci .But the magnetic resistance type read the component is then opposite more narrow, thus at read a way of ci was bigger to the tolerance degree that be partial to the track.And, the density of the way of ci can also raise immediately.
The magnetic resistance head read the component work, the electric current will has been pass the magnetic resistance head, but the electric resistance value of the magnetic resistance head would along with the dissimilarity but varieties of the magnetic field strength, so cause the electric current size change.But the traditional way then makes use of the ci to respond to produce the electric current, this is your biggest dissimilarity.Because the magnetic resistance head's variety toward magnetic field has the very high and intelligent degree, strengthen the difference between the data signal and the noise signal, so the letter zao peter arrived the very big exaltation.
The PRML read the passage hard drive capacity promotes to read with it the improvement of the passage also has the very close relation.Traditionally read the passage adoption is" the pulse examination( the Pulse Detect)" method, head from the diskette read each signal saves with the examination of data.It will set a critical value to judge whether signal is valid or not, when a signal is weaker, the data that acquisition get may have the mistake.Moreover, be to record the signal strength to attain some one degree, also may result in two signals are mutually the phenomenon of the interference.So after density of ci arrives some one degree, this kind of phenomenon would be more serious.
For resolving this problem, the people joined the PRML ―― to apply a kind of technique that corresponds by letter in the space in the design of the hard drive.Develop the PRML purpose at the beginning is for the sake of space the data to correspond by letter it with, it is the application at the earliest stage in the number cosmos airship of the wei city from the Mars transmission data going to the permafrost process, because can acquire the clear data signal.
The so-called PRML( the part respond to, biggest match, the Partial Response Maximum Likelihood) read the passage method can in brief dichotomous part to say.First is take into head from the signal that diskette read the numeral turn, and the signal that will did not reach the standard abandon, but have no direct output signal.This part calls it as" the part respond to( the Partial Response)" then.But" biggest match( the Maximum Likelihood)" part then takes after numeral turn of the signal model database of the signal model and chip of PRML take into the contrast, find out to near to, lose most a minimum signal model, re- combine these signals again but direct export data.
Use the method of PRML, don't need the so high signal strength of the elephant pulse examination method, can also avert from the creation is mutually the phenomenon of the interference because the signal record is too intensive, so the adoption PRML way can with significant raise the disk surface density.Speed continuously of deliver and connect
The more early hard drive use of is a kind of to be be called the ST506/412 connects.This from the seagate company at 1980 produce a 5.25 inches of hard drive ST506s of the first set put forward.Use this data line and one 34 control lines of the needles of that connects the oscular hard drive to need one 20 needles of, and still have to put on a quick price not the control card of the fei .The performance of the ST506/412 is not exhausted such as person's idea, and the hard drive system had the very high specific weight in the whole set of cost in the equipments, so appeared the IDE to connect.
IDE, the formal name is the AT Attachment, ATA.This kind of connect to gather controller and actuators at together, as a result saved to connect a people's expenses availably, and make the realization of the firmware become more simple.This kind of cheapness and gather in brief present the one prosperity in the disk actuator industry immediately, and the manufactory of PC also would like to adopt this kind of cheap substitute very much.In 80's, the IDE has already become the head that the commonness purchases' choose.The ATA-2 and ATA-3s be the hard drive technical development and softwares to need of raise continuously to make the ATA connect the oscular capacity to become finally mutually the form sees the 绌 , representative SFFC( the Small Form Factor Commitee) of the actuator industry drew up a kind of and permit the ATA to expand the ― - ATA-2.This standard not only increases the faster than ATA mode of PIO and mode of DMAs but also returns to be rated as to leap hugely because put forward" the actuator identify" order.At this time, the actuator can tell the software more and accurately to belong to sex ownly, but this for plug-and-play of realization is to have the function of decision.In addition, in this standard, still put forward a kind of look for the address hard drive is of the new way ―― LBA of an area, it broke the well-known 504 MB extreme limit.
The ATA-3 is 1 to the ATA-2 to revise.Among them, the part of the key include:The credibility for improving, is also such in the 4 times of mode of PIO particularly;A kind of simple of according to safe project of the password;The more outstanding power supply manage;And allow the mistake that the actuator aims at the particular type to send out the warning of from monitor, analysis and the report technique( S.M.A.R.T).The ATA-3 did not define the faster mode, although some factories released so-called" mode 5" equipments, in fact and basically has no more than 4 modes of PIO of mode of PIO ATA-2.The ATAPI ATA of of one of the weakness be what it is just for the hard drive to design.If return to the upscale PC however is take a soft get rid of and a 40 MB hard drive of ages, this is perhaps already all right already.But the CD- ROM of today and the magnetic tape equipmentses were already the very common equipmentses, but they should circulate completely at the connect of the same of cheapness on.
The ATAPI( the ATA Packet Interface) is the equipments that the design uses to come the CD- ROM and type of tape drives to insert the common port of ATA.The main advantage of the hardware of ATAPI lies in its cost low and be applicable to the any IDE or EIDEs proper go together with the machine.The " soft" tape drive of good enough to and in general use QIC117 of function and credibilities that APATI tape drive have matches in excellence mutually.
Have you 1:00 must what to clear up is, although the ATAPI can insert the IDE to connect, they still have the very big differentiation with hard drive of IDE.Unless the support ATAPI, otherwise the hard drive saves controller or other intelligenceses to connect to basically have no effect slowly.And also need the latest support of BIOS from the ATAPI CD- ROM leading.Fast- ATA and EIDE first, we should definitely 1:00, it is the technical term on the technique that these two standards say with it, saying rather to is the outcome of the marketing.The EIDE is to be draw up by the WD of, it build up at two realistic standards on:ATA-2 and ATAPI.But the Fast- ATA then is put forward by the seagate, then get the quantem support of, however it supports the ATA-2 only.
Delivering the mode( mode of PIO 3 and 4, the mode of multiword DMA 1 and 2) quickly is Fast- ATA and EIDE sills.In addition to these, the EIDE main contents have:Support the mode of LBA, allow four set equipmentses to link the ATA to connect up, support the IDE from the port, have no restrict of 504 MBs under the DOS, can pass the ATAPI conjunction CD- ROM and magnetic tape backup equipmentses.And the Fast- ATA also supports LBA's look for the address method.Moreover it still includes to read/ write the compound order( also is call a piece of mode), it passes an area number that increment deliver to reduce the interruption number of times, thus lowering the processor to take up the rate.
Still have a kind of SCSI to pick up a people's everyone to also certainly heard moreover, now, main planks of the majority all have already gather the IDE control connects, so the user basically does not need to give a lot of care again to buy a cake of to connect a people's card exclusively, have ever had the factory to say, if SCSI control chip only USD a, and gather it go to the main plank up, so the IDE connect to only have to is stood by side.This in fact also a why the IDE pick up a people widely for popular reason, because in view of a certain angle, it almost is complete free.Why to want the Ultra ATA?
The processor speed of the continuous growth, the document size that inflate continuously, the operate system of the multi-threading, the total line of the higher bandwidth, more the hard drive ―― of the high performance demand of these speeds flooded our table's top system.The fact prove that the hard drive speed is a capacity nature that wears the actuator to expand of, the traditional disk actuator industry each 18 monthses turn over saving capacity of disk a lot of.This passes two kinds of methods to carry out:One is to let the way of ci on the disk closed to( a density of ci ) more;Two is to let write more close( the line density) in the data on the way of ci , usually they press together of comparison improvement.Do like this the result cause be, the line density turn over every three years a lot of.But this will make the internal data of disk deliver the rate to turn over immediately after doubly, because when the disk turns to move each time a turn, would there are more datas can provide to spread the usage.In addition, deliver the rate because of the internal data of the disk to be decided by the line density and turn at the same time soon, so raise to turn constantly and also will speed the exaltation that the internal data delivers the rate soon.
Now, more and more big procedure, gather to the multimedia appliedly, make the size of the document with make stare tongue-tied speed of person increase.On a hard drive that has no fragment, these documents are all usually the ―― ci way that the sequence write ins immediately after way of ci .At this time, the large document deliver and would be under the influence of exterior delivering the speed very greatly.This is because when the sequence read, the actuator that has the high and internal data to deliver the rate fill the speed of buffer and may be more pure than host empty quickly have to have another.Show us this is why?The not enough well total line make use of
Can keep in many high actuators of mi with the speed of the 10 MBs/ s to save the sequence to lose the data slowly.You will say perhaps, since the exterior deliver the speed and can attain the 16.7 MBs/ s, so the Fast ATA should can avoid very easily saving the spillage slowly.The problem lies in the instruction that it still needs to spend to take a lot of time to handle the host machine( PC).The total line of this kind of instruction processing time ―― proceeds from the spare time appearance ―― at this time the affirmation is a depletion to total line, and is a count for much part in the whole depletion.
The valid data delivers time to be equal to the abrupt data to deliver time to subtract the instruction processing time, so the latter is to make the Fast ATA delivered the rate to make use of the not enough full reason effectively.Return the root exactly, the reason lie in PC that is the host's can't use the total line of ATA adequately.
The instruction processing time would along with host toward the quantity but growths of the order that actuator send out, but the mandatory quantity is decided by the size of the data claim again.These claims are usually 4 KBses, but this is similar to adoption the page size that the operate system of the virtual memory support.Underneath, we to make a calculation.
When put off to a later time to save to win the data of read the 4 KBs with the in proper order data baud rate of the 10.2 MBs/ s, the actuator needs time of 400 the milli- seconds about.Suppose the abrupt data baud rate of the Fast ATA is a 16.7 MBs/ s, so the pure empty 4 KBs of host saves to need 250 slowly.At this time, have 150 the milli- second can be provided as the instruction usage ―― it uses to come at save slowly pure empty and fill to operate carry on the balance.Regret of is, the quickest set type machine also needs the instruction processing time of 275 the milli- seconds.By so doing, the pure empty 4 KBs saves and then need 525 slowly, this was as low as the valid baud rate of the Fast ATA about the 7.8 MBs/ s.(4096 word stanzas in addition to with 525 the milli- second)Compare with the abrupt baud rate of the 16.7 MBs/ s, this is doubtless slow many.
At the same time, the 7.8 MBs/ s also onlies have 75% ―― of the in proper order baud rate of the 10.2 MBs/ s this mean to have three word stanzas to send out each time to the host, there will be a word stanza to be detained in slowly save.Thus, have unit and save the data and will be be detained slowly every three units slowly save data send out to host, would, but actuator must" get empty to turn" is a to allow the host pure empty save slowly.In consideration of the slowly save of the typical model size is a 64 KBs, so read and write the 256 KBs and will get empty to turn a ―― each time this is the waste to the actuator utilization obviously.Solution
The bottleneck that makes ATA no longer become the system can have a few methods.Among them having two kinds of solution is not the disk actuator the factory can control of of.Most direct of, is also the most difficult way is to try to reduce the order processing time.For this kind of way, the speed of the exaltation processor is a kind of to go of valid means, but see with the development speed of now, we only re- build up the structure that breaks off to have the initiative the class and then can get the decisive breakthrough on the function enough.
The more simple method of another may be the size of the data piece that raises the host to request toward actuator.For example, turn over the claim size from the 4 KBs doubly to the 8 KBs equal to handle time to the fixed instruction to reduce the half.If pass the future agreement alteration or the hardware modification( for example reduce the electric cable length, etc.)s and can't expand the ATA to the 33 MBs/ s above, increase the size of claim and may be the most actual method so.
The most traditional method raises the abrupt data baud rate in the system class, thus, actual use and will reduce to putting off to a later time to save time of deliver the data.But this is the Ultra ATA to to do of.The Ultra ATA solves the way to speak in a specific way, under the condition of using the abrupt baud rate of 33 MBs/ s of the Ultra ATA, the data piece of the 4 KBs needs only 125 the milli- second deliver time.Have thus 275 the milli- second canned be provided to consume.But this orderanies time that processing need exactly.At this time, save slowly and then will not be detained again the data, the actuator also dided not need" get empty to turn".
So how attain the 33 MBs/ s, also is to make abrupt data baud rate turn over doubly?A design that breaks sex is a rising in pulse of STROBE and descend the edge to deliver the data at the same time.At past, the Fast ATA just makes use of the STROBE rising of the data to follow the time pulse that the conduct and actions delivers the data.But why the disadvantage use the same descend existently follow?Pass to use these two edges, the Ultra ATA deliver the rate to the frequency( this kind of the exaltation will cause the emergence of the voice of zao ) ―― thus abrupt data that delivered the rate to increase 200% ―s― and actually basic need not exaltation STROBE pulses availably and also have to arrive to turn over doubly, also is to attain the 33 MBs/ s.
However, what to need to be explain is, the 33 MBs/ s is just a theories data, although we a few hard drives test this time all support the Ultra DMA/33, have no who can attain this extreme limit.In our data, the internal data delivers the rate quickest seagate" big ash bear" hard drive to also only have the 24 MBs/ s(192 Mbs/ s in addition to with 8), but the exterior data delivers the rate is impossible to exceed the internal velocity of, so can say that return to have no the hard drive of any factory and can attain this velocity of 33 MBs/ s now.IEEE1394:The standard IEEE1394 of latent future builds up in the PC and of the product of consumption A/ V a contact of 纽 take of technique.It allow the product of A/ V and can establish to work so outside like the multimedia that one pedestal is real, but the PC can become a real consumption equipments of pedestal.Had the IEEE1394, the OEM can satisfy the customer to establish to link outside the PC and audio frequency, video frequencies and the commonness multimedias of need.
The IEEE1394 uses the very cheap electric cable and simple conjunction machines to prop up with each other between equipments of link several piece word audio frequencies, numerical video frequencieses, and control the letter way of information.This kind of simple conjunctionses all have to deliver the rate and stabilities very and highly, and solid hour data processing ability, and the cheap price of IEEE1394 make applied procedures of the great majority for its all very ideal.1394 abilities of the plug-and-plays and the heat that did not need the electricity and re- starts put to pull out function is with consume the product gather of key.
EEE1394 a count for much function is an on an equal footing correspondence, this make consume a product under the condition of did not need to pass the center node( such as PC) obtain the road from the information, can correspond by letter each other directly.More important is, now only have the IEEE1394 and can carry out the PC that is shown as diagram and consume the conjunction of a product.( such as video recorder)
1394 cores of the conjunctions are a physics layer and a network layer semi-conductor chips.The physics layer chip is 1394 signal admixture equipmentses of the ports of a with many support.It includes to carry out the total line to arbitrate to start the logic of turn the function with beginning.The network layer chip transmission and receive the data that was turned by 1394 formats to wrap, and support a data's deliver.Deliver synchronously the ability make PC can more for handle availably to compare the typical model in multimedia apply of high bandwidth data flow.But when gather the product of A/ V arrive to use the PC hard drive to be used as the system China Times that the data saves the equipments, a data processing of the high class then will have the value very much.ATA of two kinds of deliver the mode ATA hard drive contain two kinds of mode of PIO and mode of DMA deliver the way.The PIO is the abbreviation of the Programmed Input Output( the programmable importation output).Elfevident, it is take into the process that the data deliver the procedure turn, but this will aggravate the CPU burden obviously.Therefore under this kind of mode, is a CPU efficiency even if very high, but because it must with all strength the whereabouts reason data access, so can't do again the another affair.The current PIO has 1,2,3 and 4 four kinds of modes.
Everyone of DMA acquaints with very much, it is the Direct Memory Access, the abbreviation of the direct memory interview.But the ATA the DMA mode nature is to delivered the hard drive data through a passage of DMA.The mode of DMA makes the Single Word and two kinds of modes of the Multi Word separately again, they and mode of PIO to should of velocity see" the ATA delivers the mode and velocities".Total and linear theories baud rate Single word DMA 02.1 MBs/ s of IDE( ATA)
PIO mode 03.3MB/s
The Single word DMA 1, the DMA 04.2 MBs/ s of multi word
PIO mode 15.2MB/s
The PIO mode 2, the DMA 28.3 MBs/ s of single word
Total and linear theories baud rate PIO mode 311.1 MBs/ s of ATA-2
Multi word DMA 113.3MB/s
The PIO mode 4, the DMA 216.6 MBs/ s of multi word
The theories baud rate Multi word DMA 333.3 MBs/ sS.M.A.R of the Ultra- ATA. T:When protect an absolute being or a watchdog is the person to be depend on in a thing more and more, will produce the crisis on the question of confidence gradually.The hard drive is an essential saving equipments of modern customer, because compare with other saving equipmentses, the hard drive has the access fast, cheap advantage of convenience and prices of usage.But when all se advantages can carry out, the people bring about doubt on its credibility then.With the exaltation hard drive capacity, speed the access speed to compare, the people are morely what to consider is own data to have many safeties exactly on the hard drive.Enlarge continuously along with the hard drive capacity, the people is more and more at the data that deposit up, this kind of crisis feeling also let person have no peace of mind day and night more and more.
S.M.A.R.T is from monitor, analysis and report the technical brief name.The new function that this kind of current new hard drive systemses all have can say that temporarily alleviates a good medicine of this kind of problem.This technique can apply on the ATA or hard drive of SCSIs.It was put forward by the Compaq at the earliest stage, the Compaq just hoped at first its hard drive supplier can join and can keep watch on by one's own in the design of the hard drive with the ability of analytical various parameter, by this analytical hard drive whether normal, in order to notify the system in advance, adopt to various possible breakdown to should measure.Afterwards each big hard drive factory is in the specification of the ATA-3 the formality takes S.M.A.R.T into the standard.The work mechanism
After hard drive start, the procedure of the tiny controller woulds be automatic, keeps on and periodically supervises and control some items then on the hard drive, once the number supervise and control is is low in critical value, will notify the system then, warn may have problems the occurrence.But the scope big part that it keep watch on is a machine up of wear away or the output's signal abnormality, but for sudden breakdown, for example the machine spare parts splits suddenly or expired, the S.M.A.R.T felt helpless.Also is to say, the breakdown that it can predict is in the surveillance of the long-term, there is vestige the breakdown that can follow, if abrupt type, certainly can't predict out.Right understanding
Although the technical emergence of S.M.A.R.T makes the safety of the data get the very big exaltation doubtless.But is not to own this technique, end customer can with high 枕 without sorrow, need not do again what backup.Positive such as we the top see of, this technique can't predict an all breakdown out and out also.Therefore, not want the S.M.A.R.T see is the hard drive system of protection absolute being, it just is most a watchdog, the protection absolute being can prevent disaster to do not need the disaster for you, but watchdog only the thief that ability is small to burglar to touch yells several voices, meet up the cruelty and arrogant river ocean thief possibility can become the at one feed delicacy good dinner only.The different from SCSI, applied choice of IDE did not need to be say much, you will discover to gather plus the hard drive of EIDE to want to be cheaper than actuator of SCSI and have to have another in the controller of EIDE of the main plank.To use the SCSI, you still need to be an additional proper go together with the machine( connect a people's card), this is because most main planks do not gather controller of SCSI.By so doing, and expensive disk of SCSI, the system of SCSI want to be more expensive than system of EIDE up many.
The EIDE has a main passage and a from the passage, each one can link two set equipmentses, add altogether four.This can be the hard drive, can also be a CD- ROM.Thered has been taking the tape drive of the EIDE conjunction machine now, but you need the special backup software.
In the passage of IDE, two equipmentses control the total and linear by turn.If have a hard drive and a CD- ROMs on the same of passage, so the hard drive must wait for the claim that CD- ROM send out be complete.Because the CD- ROM is opposite to say that want to be slowly some, so this will cause the function last and compromised necessarily.This be why everybody will tell that you link the CD- ROM from the passage, but the reason that your hard drive establishes for the main equipments.Main passage and from the passage or many or little with mutually independent way work of.( this is attributed to the EIDE controller chip)
The SCSI connect contain several categories type.8(50 needle data electric cables) or 16.(68 needle data electric cables, the Wide SCSI)The clock frequency contain 5 MHzs( SCSI 1),10 MHzs( the Fast SCSI),20 MHzs( Fast-20 or the Ultra SCSI) or 40 MHzs( SCSIs Ultra-2).It is a kind of line with total microcomputer physically, it gather all of the functions of the disk controller arrived the equipments in the middle, and still increased the SCSI to connect a people's control electric circuit in the equipments.The theories baud rate SCSI total line clock frequency of the total line of SCSI 8165 MHzses( SCSI 1)5 MBs/ s N/ A10MZ( the Fast SCSI, the SCSI II)10 MBs/ s 20 MBs/ s20MHz( Fast-20, the Ultra SCSI)20 MBs/ s 40 MBs/ s40MHz( Fast-40, the Ultra SCSI)40 MBs/ s 80 MBs/ s SCSI connect is establishes outward with the host system of unify the total line of I/ O of form appear of, it be placed in the host proper go together with the machine( the SCSI connects a people's card) with the that establish the controller outside, it not only can control the disk actuator, but also can control the tape drive, etc. establish outside, but have a prior condition, be these establish to win outside and must include own controller.
Scanner and many CD- Wses have no EIDE to connect, they can pass the conjunction of SCSI only.You can be total and on-line in a SCSI to link 7 set equipmentses, or link 15 set equipmentses on the Wide SCSI.In the environment of the standard, the function of a hard drive will not have the too big exaltation also because the usage SCSI connects.The SCSI power lie in several equipmentses' can use the total line at the same time, not just use under the condition that other people do not need.So, when a few equipmentses all use same total line at the same time, you will slice the body to feel the SCSI advantage.Under many environments of mission, the SCSI advantage is also a body now thoroughly, because usually take place to visit at the same time at this time.If you have a server to want to use the document of the big size perhaps, such as audio frequency, video frequency or disk intensive application of the type, SCSI meeting the body appears an EIDE an etc. of everyone's manner.