ÆROM: GARYF@WIIS.WANG.COM (ÇARY ÆIELD) ÓUBJECT: COMP.PERIPHS.SCSI ÆÁÑ PART 2 OF 2 ÅXPIRES: ÆRI, 1 ÊUL 1994 05:00:03 ÇÍÔ ÒEPLY-ÔO: GARYF@WIIS.WANG.COM (ÇARY ÆIELD) ÏRGANIZATION: ×ANG ÌABS, ÌOWELL ÍÁ, ÕÓÁ ÄATE: ÔHU, 2 ÊUN 1994 13:27:35 ÇÍÔ ÁPPROVED: NEWS-ANSWERS-REQUEST@ÍÉÔ.ÅDU ÍESSAGE-ÉÄ: <ÃQRUPZ.ÍZÇ@WANG.COM> ÆOLLOWUP-ÔO: COMP.PERIPHS.SCSI ÓUMMARY: ÔHIS POSTING CONTAINS A LIST OF ÆREQUENTLY ÁSKED ÑUESTIONS (AND THEIR ANSWERS) ABOUT ÓÃÓÉ. ÉT SHOULD BE READ BY ANYONE WHO WISHES TO POST TO THE COMP.PERIPHS.SCSI NEWSGROUP. ÓENDER: NEWS@WANG.COM ÎNTP-ÐOSTING-ÈOST: GFIELD.WIIS.WANG.COM ÌINES: 1127 ØREF: MMDDVAN COMP.PERIPHS.SCSI:23543 COMP.ANSWERS:5633 NEWS.ANSWERS:23176 ÁRCHIVE-NAME: SCSI-FAQ/PART2 ÓÃÓÉ ÆÁÑ: ÆREQUENTLY ÁSKED ÑUESTIONS FOR COMP.PERIPHS.SCSI ÖÏÌÕÍÅ ÉÉ ÖOLUME ÉÉ ÔABLE OF ÃONTENTS: ×HAT IS THE DIFFERENCE BETWEEN ÓÃÓÉ-1 AND ÓÃÓÉ-2? ÉS ÓÙÎÃÈÒÏÎÏÕÓ FASTER THAN ÁÓÙÎÃÈÒÏÎÏÕÓ? ÉS THE 53Ã90 ÆASTER THAN SPEC? ×HAT ARE THE JUMPERS ON MY ÃONNER DRIVE? ×HAT ARE THE JUMPERS FOR MY ×ANGTEK 5150 DRIVE? ×HAT IS ÃÁÍ? ×HAT IS ÆÐÔ (ÔERMINATION)? ×HAT IS ÁCTIVE ÔERMINATION? ×HY ÉS ÁCTIVE ÔERMINATION ÂETTER? ×HY IS ÓÃÓÉ MORE EXPENSIVE THAN ÉÄÅ? ×HAT IS ÐLUG AND ÐLAY ÓÃÓÉ? ×HERE CAN É GET DRIVERS (ÁÓÐÉ AND OTHER) FOR THE ×Ä7000 ÆÁÓÓÔ2 HOST ADAPTER? ×HAT IF É HAVE A DRIVE LARGER THAN A GIGABYTE (1024K) ? ==== ÑÕÅÓÔÉÏÎ: ×HAT IS THE DIFFERENCE BETWEEN ÓÃÓÉ-1 AND ÓÃÓÉ-2? ÁÎÓ×ÅÒ ÆROM ÄAL ÁLLEN: ==== ÓÃÓÉ-1ßVERSUSßÓÃÓÉ-2 ÉN 1985, WHEN THE FIRST ÓÃÓÉ STANDARD WAS BEING FINALIZED AS AN ÁMERICAN ÎATIONAL ÓTANDARD, THE Ø3Ô9.2 ÔASK ÇROUP WAS APPROACHED BY A GROUP OF MANUFACTURERS. ÔHE GROUP WANTED TO INCREASE THE MANDATORY REQUIREMENTS OF ÓÃÓÉ AND TO DEFINE FURTHER FEATURES FOR DIRECT-ACCESS DEVICES. ÒATHER THAN DELAY THE ÓÃÓÉ STANDARD, Ø3Ô9.2 FORMED AN AD HOC GROUP TO DEVELOP A WORKING PAPER THAT WAS EVENTUALLY CALLED THE ÃOMMON ÃOMMAND ÓET (ÃÃÓ). ÍANY PRODUCTS WERE DESIGNED TO THIS WORKING PAPER. ÉN PARALLEL WITH THE DEVELOPMENT OF THE ÃÃÓ WORKING PAPER, Ø3Ô9.2 SOUGHT PERMISSION TO BEGIN WORKING ON AN ENHANCED ÓÃÓÉ STANDARD, TO BE CALLED ÓÃÓÉ-2. ÓÃÓÉ-2 WOULD INCLUDE THE RESULTS OF THE ÃÃÓ WORKING PAPER, CACHING COMMANDS, PERFORMANCE ENHANCEMENT FEATURES, AND WHATEVER ELSE Ø3Ô9.2 DEEMED WORTHWHILE. ×HILE ÓÃÓÉ-2 WAS TO GO BEYOND THE ORIGINAL ÓÃÓÉ STANDARD (NOW REFERRED TO AS ÓÃÓÉ-1), IT WAS TO RETAIN A HIGH DEGREE OF COMPATIBILITY WITH ÓÃÓÉ-1 DEVICES. ÈOW IS ÓÃÓÉ-2 DIFFERENT FROM ÓÃÓÉ-1? 1. ÓEVERAL OPTIONS WERE REMOVED FROM ÓÃÓÉ-1: A. ÓINGLE INITIATOR OPTION WAS REMOVED. B. ÎON-ARBITRATING ÓYSTEMS OPTION WAS REMOVED. C. ÎON-EXTENDED SENSE DATA OPTION WAS REMOVED. D. ÒESERVATION QUEUING OPTION WAS REMOVED. E. ÔHE READ-ONLY DEVICE COMMAND SET WAS REPLACED BY THE ÃÄ-ÒÏÍ COMMAND SET. F. ÔHE ALTERNATIVE 1 SHIELDED CONNECTOR WAS DROPPED. 2. ÔHERE ARE SEVERAL NEW LOW-LEVEL REQUIREMENTS IN ÓÃÓÉ-2: A. ÐARITY MUST BE IMPLEMENTED. B. ÉNITIATORS MUST PROVIDE ÔÅÒÍÐ×Ò -- ÔARGETS MAY PROVIDE ÔÅÒÍÐ×Ò. C. ÔHE ARBITRATION DELAY WAS EXTENDED TO 2.4 US FROM 2.2 US. D. ÍESSAGE SUPPORT IS NOW REQUIRED. 3. ÍANY OPTIONS SIGNIFICANTLY ENHANCING ÓÃÓÉ WERE ADDED: A. ×IDE ÓÃÓÉ (UP TO 32 BITS WIDE USING A SECOND CABLE) B. ÆAST ÓÃÓÉ (SYNCHRONOUS DATA TRANSFERS OF UP TO 10 ÍEGA-TRANSFERS PER SECOND -- UP TO 40 ÍEGAÂYTES PER SECOND WHEN COMBINED WITH WIDE ÓÃÓÉ) C. ÃOMMAND QUEUING (UP TO 256 COMMANDS PER INITIATOR ON EACH LOGICAL UNIT) D. ÈIGH-DENSITY CONNECTOR ALTERNATIVES WERE ADDED FOR BOTH SHIELDED AND NON- SHIELDED CONNECTORS. E. ÉMPROVED TERMINATION FOR SINGLE-ENDED BUSES (ÁLTERNATIVE 2) F. ÁSYNCHRONOUS EVENT NOTIFICATION G. ÅXTENDED CONTINGENT ALLEGIANCE H. ÔERMINATE É/Ï ÐROCESS MESSAGING FOR TIME- CRITICAL PROCESS TERMINATION 4. ÎEW COMMAND SETS WERE ADDED TO ÓÃÓÉ-2 INCLUDING: A. ÃÄ-ÒÏÍ (REPLACES READ-ONLY DEVICES) B. ÓCANNER DEVICES C. ÏPTICAL MEMORY DEVICES (PROVIDES FOR WRITE-ONCE, READ-ONLY, AND ERASABLE MEDIA) D. ÍEDIUM CHANGER DEVICES E. ÃOMMUNICATIONS DEVICES 5. ÁLL COMMAND SETS WERE ENHANCED: A. ÄEVICE ÍODELS WERE ADDED B. ÅXTENDED SENSE WAS EXPANDED TO ADD: + ÁDDITIONAL SENSE CODES + ÁDDITIONAL SENSE CODE QUALIFIERS + ÆIELD REPLACEABLE UNIT CODE + ÓENSE KEY SPECIFIC BYTES C. ÉÎÑÕÉÒÙ ÄÁÔÁ WAS EXPANDED TO ADD: + ÁN IMPLEMENTED OPTIONS BYTE + ÖENDOR IDENTIFICATION FIELD + ÐRODUCT IDENTIFICATION FIELD + ÐRODUCT REVISION LEVEL FIELD + ÖITAL PRODUCT DATA (MORE EXTENSIVE PRODUCT REPORTING) D. ÔHE ÍÏÄÅ ÓÅÌÅÃÔ AND ÍÏÄÅ ÓÅÎÓÅ COMMANDS WERE PAGED FOR ALL DEVICE TYPES E. ÔHE FOLLOWING COMMANDS WERE ADDED FOR ALL DEVICE TYPES: + ÃÈÁÎÇÅ ÄÅÆÉÎÉÔÉÏÎ + ÌÏÇ ÓÅÌÅÃÔ + ÌÏÇ ÓÅÎÓÅ + ÒÅÁÄ ÂÕÆÆÅÒ + ×ÒÉÔÅ ÂÕÆÆÅÒ F. ÔHE ÃÏÐÙ COMMAND DEFINITION WAS EXPANDED TO INCLUDE INFORMATION ON HOW TO HANDLE INEXACT BLOCK SIZES AND TO INCLUDE AN IMAGE COPY OPTION. G. ÔHE DIRECT-ACCESS DEVICE COMMAND SET WAS ENHANCED AS FOLLOWS: + ÔHE ÆÏÒÍÁÔ ÕÎÉÔ COMMAND PROVIDES MORE CONTROL OVER DEFECT MANAGEMENT + ÃACHE MANAGEMENT WAS ADDED: - ÌÏÃË/ÕÎÌÏÃË ÃÁÃÈÅ COMMAND - ÐÒÅÆÅÔÃÈ COMMAND - ÓÙÎÃÈÒÏÎÉÚÅ ÃÁÃÈÅ COMMAND - ÆORCE UNIT ACCESS BIT - ÄISABLE PAGE OUT BIT + ÓEVERAL NEW COMMANDS WERE ADDED: - ÒÅÁÄ ÄÅÆÅÃÔ ÄÁÔÁ - ÒÅÁÄ ÌÏÎÇ - ×ÒÉÔÅ ÌÏÎÇ - ×ÒÉÔÅ ÓÁÍÅ + ÔHE SEQUENTIAL-ACCESS DEVICE COMMAND SET WAS ENHANCED AS FOLLOWS: - ÐARTITIONED MEDIA CONCEPT WAS ADDED: * ÌÏÃÁÔÅ COMMAND * ÒÅÁÄ ÐÏÓÉÔÉÏÎ COMMAND - ÓEVERAL MODE PAGES WERE ADDED - ÂUFFERED MODE 2 WAS ADDED - ÁN IMMEDIATE BIT WAS ADDED TO THE ×ÒÉÔÅ ÆÉÌÅÍÁÒËÓ COMMAND + ÔHE PRINTER DEVICE COMMAND SET WAS ENHANCED AS FOLLOWS: - ÓEVERAL MODE PAGES DEFINED: * ÄISCONNECT/RECONNECT * ÐARALLEL PRINTER * ÓERIAL PRINTER * ÐRINTER OPTIONS + ÔHE WRITE-ONCE (OPTICAL) DEVICE COMMAND SET WAS ENHANCED BY: - ÓEVERAL NEW COMMANDS WERE ADDED: * ÍÅÄÉÕÍ ÓÃÁÎ * ÒÅÁÄ ÕÐÄÁÔÅÄ ÂÌÏÃË * ÕÐÄÁÔÅ ÂÌÏÃË - ÔWELVE-BYTE COMMAND DESCRIPTOR BLOCKS WERE DEFINED FOR SEVERAL COMMANDS TO ACCOMMODATE LARGER TRANSFER LENGTHS. ============================================================================= ÔHE FOLLOWING ARTICLE WAS WRITTEN BY ÄAL ÁLLAN OF ÅÎÄÌ IN ÁPRIL 1990. ÉT WAS PUBLISHED NINE MONTHS LATER IN THE ÊANUARY 1991 ISSUE OF "ÃOMPUTER ÔECHNOLOGY ÒEVIEW". ×HILE IT APPEARED IN THE ÔAPE ÓTORAGE ÔECHNOLOGY ÓECTION OF ÃÔÒ, THE ARTICLE IS GENERAL IN NATURE AND TAPE-SPECIFIC. ÉN SPITE OF THE LESS THAN TIMELY PUBLICATION, MOST OF THE INFORMATION IS STILL VALID. ÉT IS REPRINTED HERE WITH THE PERMISSION OF THE AUTHOR. ÉF YOU COPY THIS ARTICLE, PLEASE INCLUDE THIS NOTICE GIVING "ÃOMPUTER ÔECHNOLOGY ÒEVIEW" CREDIT FOR FIRST PUBLICATION. ------------------------------------------------------------------------------ ×HAT'S ÎEW IN ÓÃÓÉ-2 ÓCUZZY IS THE PRONUNCIATION AND ÓÃÓÉ (ÓMALL ÃOMPUTER ÓYSTEM ÉNTERFACE) IS THE ACRONYM, FOR THE BEST KNOWN AND MOST WIDELY USED ÁÎÓÉ (ÁMERICAN ÎATIONAL ÓTANDARDS ÉNSTITUTE) INTERFACE. ÄESPITE USE OF THE TERM "ÓMALL" IN ITS NAME, EVERYONE HAS TO AGREE THAT ÓCUZZY IS LARGE - IN USE, IN MARKET IMPACT, IN INFLUENCE, AND UNFORTUNATELY, IN DOCUMENTATION. ÔHE STANDARDS EFFORT THAT BEGAN WITH A 20-PAGE SPECIFICATION IN 1980 HAS GROWN TO A 600 PAGE EXTRAVAGANZA OF TECHNICAL INFORMATION. ÅVEN BEFORE ÁÎÓÉ (ÁMERICAN ÎATIONAL ÓTANDARDS ÉNSTITUTE) PUBLISHED THE FIRST RUN OF ÓÃÓÉ AS STANDARDS DOCUMENT IN 1986, ÁÓà (ÁCCREDITED ÓTANDARDS ÃOMMITTEE) Ø3Ô9.2 WAS HARD AT WORK ON ÓÃÓÉ-2. ÎO TECHNICAL RATIONALE CAN BE OFFERED AS TO WHY ÓÃÓÉ-1 ENDED AND ÓÃÓÉ-2 BEGAN, OR AS TO WHY ÓÃÓÉ-2 ENDED AND ÓÃÓÉ-3 BEGAN. ÔHE JUSTIFICATION IS MUCH MORE SIMPLE - YOU HAVE TO STOP SOMETIME AND GET A STANDARD PRINTED. ÐOPULAR INTERFACES NEVER STOP EVOLVING, ADAPTING, AND EXPANDING TO MEET MORE USES THAN ORIGINALLY ENVISAGED. ÉNTERFACES EVEN LIVE FAR BEYOND THEIR TECHNOLOGICAL LIFESPAN. ÓÍÄ (ÓTORAGE ÍODULE ÄRIVE) HAS BEEN CALLED TECHNICALLY OBSOLETE FOR 5 YEARS BUT EVERY YEAR THERE ARE MORE MEGABYTES SHIPPED ON THE ÓÍÄ INTERFACE THAN THE YEAR BEFORE. ÔHIS WILL PROBABLY CONTINUE FOR ANOTHER YEAR OR SO BEFORE THE HIGH POINT IS REACHED, AND IT WILL AT LEAST A DECADE BEFORE ÓÍÄ IS CONSIDERED TO BE INSIGNIFICANT. ÉF ÓÃÓÉ ENHANCEMENTS ARE CUT OFF AT AN ARBITRARY POINT, WHAT INITIATES THE DECISION? ÉMPATIENCE IS AS GOOD AN ANSWER AS ANY. ÔHE COMMITTEE AND THE MARKET GET SICK OF PROMISES THAT THE REVISION PROCESS WILL "END SOON," AND ASSERT PRESSURE TO "DO IT NOW." ÔHE ÓÃÓÉ-3 EFFORT IS ACTIVELY UNDER WAY RIGHT NOW, AND THE WORKLOAD OF THE COMMITTEE SEEMS TO BE NO LESS THAN IT WAS A YEAR AGO. ×HAT IS PLEASANT, IS THAT THE POLITICAL PRESSURES HAVE EASED. ÔHERE IS A MAJOR DIFFERENCE BETWEEN THE STANDARDS FOR ÓÃÓÉ IN 1986 AND ÓÃÓÉ- 2 IN 1990. ÔHE STATED GOAL OF COMPATIBILITY BETWEEN MANUFACTURERS HAD NOT BEEN ACHIEVED IN ÓÃÓÉ IN 1986 DUE TO A PROLIFERATION OF UNDOCUMENTED "FEATURES." ÅACH IMPLEMENTATION WAS DIFFERENT ENOUGH THAT NEW SOFTWARE DRIVERS HAD TO BE WRITTEN FOR EACH DEVICE. ÏÅÍS DEFINED VARIATIONS IN HARDWARE THAT REQUIRED CUSTOM DEVELOPMENT PROGRAMS AND UNIQUE MICROCODE. ÏUT OF THIS DIVERSITY AROSE A CRY FOR COMMONALITY THAT TURNED INTO ÃÃÓ (ÃOMMON ÃOMMAND ÓET), AND BECAME SO POPULAR THAT IT TOOK ON AN IDENTITY OF ITS OWN. ÃÃÓ DEFINED THE DATA STRUCTURES OF ÍODE ÓELECT AND ÍODE ÓENSE COMMANDS, DEFECT MANAGEMENT ON THE ÆORMAT COMMAND AND ERROR RECOVERY PROCEDURES. ÃÃÓ SUCCEEDED BECAUSE THE GOALS WERE LIMITED, THE OBJECTIVES CLEAR AND THE TIME WAS RIGHT. ÃÃÓ WAS THE BEGINNING OF ÓÃÓÉ-2, BUT IT WAS ONLY FOR DISKS. ÔAPE AND OPTICAL DISKS SUFFERED FROM DIVERSITY, AND SO IT WAS THAT THE FIRST WORKING GROUP EFFORTS ON ÓÃÓÉ-2 WERE FOCUSED ON TAPES AND OPTICAL DISKS. ÈOWEVER, OPENING UP A NEW STANDARDS EFFORT IS LIKE LIFTING THE LID ON ÐANDORA'S ÂOX - IT'S HARD TO STAY FOCUSED ON A SINGLE TASK. ÓÃÓÉ-2 WENT FAR BEYOND EXTENDING AND CONSOLIDATING ÃÃÓ FOR MULTIPLE DEVICE TYPES. ÓÃÓÉ-2 REPRESENTS THREE YEARS OF CREATIVE THOUGHT BY SOME OF THE BEST MINDS IN THE BUSINESS. ÍANY OF THE NEW FEATURES WILL BE USEFUL ONLY IN ADVANCED SYSTEMS; A FEW WILL FIND THEIR WAY INTO THE AVERAGE USER'S SYSTEM. ÓOME MAY NEVER APPEAR IN ANY USEFUL FORM AND WILL ATROPHY, AS DID SOME ORIGINAL ÓÃÓÉ FEATURES LIKE ÅXTENDED ÉDENTIFY. ÂEFORE BEGINNING COVERAGE OF "WHAT'S NEW IN ÓÃÓÉ-2," IT MIGHT BE WELL TO LIST SOME OF THE THINGS THAT AREN'T NEW. ÔHE SILICON CHIPS DESIGNED FOR ÓÃÓÉ ARE STILL USABLE. ÎO NEW FEATURES WERE INTRODUCED WHICH OBSOLETE CHIPS. ÔHE CAUSE OF SILICON OBSOLESCENCE HAS BEEN RAPID MARKET SHIFTS IN INTEGRATING FUNCTIONS TO PROVIDE HIGHER PERFORMANCE. ÓIMILARLY, INITIATORS WHICH WERE DESIGNED PROPERLY, ACCORDING TO ÓÃÓÉ IN 1986, WILL SUCCESSFULLY SUPPORT ÓÃÓÉ-2 PERIPHERALS. ÈOWEVER, IT SHOULD BE POINTED OUT THAT NOT ALL THE INITIATORS SOLD OVER THE LAST FEW YEARS BEHAVED ACCORDING TO THE STANDARD, AND THEY CAN BE "BLOWN AWAY "BY ÓÃÓÉ-2 TARGETS. ÔHE 1986 STANDARD ALLOWS EITHER INITIATORS OR TARGETS TO BEGIN NEGOTIATION FOR SYNCHRONOUS TRANSFERS, AND REQUIRES THAT BOTH INITIATORS AND TARGETS PROPERLY HANDLE THE SEQUENCE. Á SURPRISINGLY LARGE PERCENTAGE OF ÓÃÓÉ INITIATORS WILL FAIL IF THE TARGET BEGINS NEGOTIATION. ÔHIS HAS NOT BEEN AS MUCH OF A PROBLEM TO DATE AS IT WILL BECOME IN THE FUTURE, AND YOU KNOW AS WELL AS É DO, THAT THESE NON-COMPLIANT INITIATORS ARE GOING TO BLAME THE ÓÃÓÉ-2 TARGETS FOR BEING "INCOMPATIBLE." ÑUIRKS IN THE 1986 STANDARD, LIKE 4 BYTES BEING TRANSFERRED ON ÒEQUEST ÓENSE, EVEN IF THE REQUESTED LENGTH WAS ZERO HAVE BEEN CORRECTED IN ÓÃÓÉ-2. ÉNITIATORS WHICH RELIED ON THIS QUIRK INSTEAD OF REQUESTING 4 BYTES WILL GET INTO TROUBLE WITH A ÓÃÓÉ-2 TARGET. Á SINCERE EFFORT HAS BEEN MADE TO ENSURE THAT A 1986-COMPLIANT INITIATOR DOES NOT FAIL OR HAVE PROBLEMS WITH A ÓÃÓÉ-2 TARGET. ÉF PROBLEMS OCCUR, LOOK FOR A NON-COMPLIANT INITIATOR BEFORE YOU BLAME THE ÓÃÓÉ-2 STANDARD. ÁFTER THAT LITTLE LECTURE, LET US TURN TO THE FEATURES YOU WILL FIND IN ÓÃÓÉ-2 WHICH INCLUDE: O ×IDE ÓÃÓÉ: ÓÃÓÉ MAY NOW TRANSFER DATA AT BUS WIDTHS OF 16 AND 32 BITS. ÃOMMANDS, STATUS, MESSAGES AND ARBITRATION ARE STILL 8 BITS, AND THE Â-ÃABLE HAS 68 PINS FOR DATA BITS. ÃABLING WAS A CONFUSING ISSUE IN THE CLOSING DAYS OF ÓÃÓÉ-2, BECAUSE THE FIRST PROJECT OF ÓÃÓÉ-3 WAS THE DEFINITION OF A 16- BIT WIDE Ð-ÃABLE WHICH SUPPORTED 16-BIT ARBITRATION AS WELL AS 16-BIT DATA TRANSFERS. ÁLTHOUGH ÓÃÓÉ-2 DOES NOT CONTAIN A DEFINITION OF THE Ð-ÃABLE, IT IS QUITE POSSIBLE THAT WITHIN THE YEAR, THE Ð-ÃABLE WILL BE MOST POPULAR NON-ÓÃÓÉ-2 FEATURE ON ÓÃÓÉ-2 PRODUCTS. ÔHE MARKET RESPONDS TO WHAT IT WANTS, NOT THE THE ARBITRARY CUTOFFS OF STANDARDS COMMITTEES. O ÆAST ÓÃÓÉ: Á 10 ÍÈZ TRANSFER RATE FOR ÓÃÓÉ CAME OUT OF A JOINT EFFORT WITH THE ÉÐÉ (ÉNTELLIGENT ÐERIPHERAL ÉNTERFACE) COMMITTEE IN ÁÓà Ø3Ô9.3. ÆAST ÓÃÓÉ ACHIEVES 10 ÍEGABYTES/SECOND ON THE Á-ÃABLE AND WITH WIDER DATA PATHS OF 16- AND 32-BITS CAN RISE TO 20 ÍEGABYTES/SECOND AND EVEN 40 ÍEGABYTES/SECOND. ÈOWEVER, BY THE TIME THE MARKET STARTS DEMANDING 40 ÍEGABYTES/SECOND IT IS LIKELY THAT THE EFFORT TO SERIALIZE THE PHYSICAL INTERFACE FOR ÓÃÓÉ-3 WILL ATTRACT HIGH-PERFORMANCE ÓÃÓÉ USERS TO THE ÆIBER ÃHANNEL. Á WORD OF CAUTION. ÁT THIS TIME THE FAST PARAMETERS CANNOT BE MET BY THE ÓINGLE ÅNDED ELECTRICAL CLASS, AND IS ONLY SUITABLE FOR ÄIFFERENTIAL. ÏNE OF THE GOALS IN ÓÃÓÉ-3 IS TO IDENTIFY THE IMPROVEMENTS NEEDED TO ACHIEVE 10 ÍÈZ OPERATION WITH ÓINGLE ÅNDED COMPONENTS. O ÔERMINATION: ÔHE ÓINGLE ÅNDED ELECTRICAL CLASS DEPENDS ON VERY TIGHT TERMINATION TOLERANCES, BUT THE PASSIVE 132 OHM TERMINATION DEFINED IN 1986 IS MISMATCHED WITH THE CABLE IMPEDANCE (TYPICALLY BELOW 100 OHMS). ÁLTHOUGH NOT A PROBLEM AT LOW SPEEDS WHEN ONLY A FEW DEVICES ARE CONNECTED, REFLECTIONS CAN CAUSE ERRORS WHEN TRANSFER RATES INCREASE AND/OR MORE DEVICES ARE ADDED. ÉN ÓÃÓÉ-2, AN ACTIVE TERMINATOR HAS BEEN DEFINED WHICH LOWERS TERMINATION TO 110 OHMS AND IS A MAJOR BOOST TO SYSTEM INTEGRITY. O ÂUS ÁRBITRATION, ÐARITY AND THE ÉDENTIFY ÍESSAGE WERE OPTIONS OF ÓÃÓÉ, BUT ARE REQUIRED IN ÓÃÓÉ-2. ÁLL BUT THE EARLIEST AND MOST PRIMITIVE ÓÃÓÉ IMPLEMENTATIONS HAD THESE FEATURES ANYWAY, SO ÓÃÓÉ-2 ONLY LEGITIMIZES THE DE FACTO MARKET CHOICES. ÔHE ÉDENTIFY MESSAGE HAS BEEN ENHANCED TO ALLOW THE TARGET TO EXECUTE PROCESSES, SO THAT COMMANDS CAN BE ISSUED TO THE TARGET AND NOT JUST THE ÌÕÎS. O ÃONNECTORS: ÔHE TAB AND RECEPTACLE MICROCONNECTORS CHOSEN FOR ÓÃÓÉ-2 ARE AVAILABLE FROM SEVERAL SOURCES. Á SMALLER CONNECTOR WAS SEEN AS ESSENTIAL FOR THE SHRINKING FORM FACTOR OF DISK DRIVES AND OTHER PERIPHERALS. ÔHIS SELECTION WAS ONE OF THE MOST ARGUED OVER AND CONTENTIOUS DECISIONS MADE DURING ÓÃÓÉ-2 DEVELOPMENT. O ÒOTATIONAL ÐOSITION ÌOCKING: Á ROSE BY ANY OTHER NAME, THIS FEATURE DEFINES SYNCHRONIZED SPINDLES, SO THAN AN INITIATOR CAN MANAGE DISK TARGETS WHICH HAVE THEIR SPINDLES LOCKED IN A KNOWN RELATIVE POSITION TO EACH OTHER. ÓYNCHRONIZED DISKS DO NOT ALL HAVE TO BE AT ÉNDEX, THEY CAN BE SET TO AN OFFSET IN TIME RELATIVE TO THE MASTER DRIVE. ÂY ARRAYING BANKS OF SYNCHRONIZED DISKS, FASTER TRANSFER RATES CAN BE ACHIEVED. O ÃONTINGENT ÁLLEGIANCE: ÔHIS EXISTED IN ÓÃÓÉ-1, EVEN THOUGH IT WAS NOT DEFINED, AND IS REQUIRED TO PREVENT THE CORRUPTION OF ERROR SENSE DATA. ÔARGETS IN THE ÃONTINGENT ÁLLEGIANCE STATE REJECT ALL COMMANDS FROM OTHER INITIATORS UNTIL THE ERROR STATUS IS CLEARED BY THE INITIATOR THAT RECEIVED THE ÃHECK ÃONDITION WHEN THE ERROR OCCURRED. ÄEFERRED ERRORS WERE A PROBLEM IN THE ORIGINAL ÓÃÓÉ BUT WERE NOT DESCRIBED. Á DEFERRED ERROR OCCURS IN BUFFERED SYSTEMS WHEN THE TARGET ADVISES ÇOOD ÓTATUS WHEN IT ACCEPTS WRITTEN DATA INTO A BUFFER. ÓOME TIME LATER, IF ANYTHING GOES WRONG WHEN THE BUFFER CONTENTS ARE BEING WRITTEN TO THE MEDIA, YOU HAVE A DEFERRED ERROR. O ÅXTENDED ÃONTINGENT ÁLLEGIANCE (ÅÃÁ): ÔHIS EXTENDS THE UTILITY OF THE ÃONTINGENT ÁLLEGIANCE STATE FOR AN INDEFINITE PERIOD DURING WHICH THE INITIATOR THAT RECEIVED THE ERROR CAN PERFORM ADVANCED RECOVERY ALGORITHMS. O ÁSYNCHRONOUS ÅVENT ÎOTIFICATION (ÁÅÎ): ÔHIS FUNCTION COMPENSATES FOR A DEFICIENCY IN THE ORIGINAL ÓÃÓÉ WHICH DID NOT PERMIT A TARGET TO ADVISE THE INITIATOR OF ASYNCHRONOUS EVENTS SUCH AS A CARTRIDGE BEING LOADED INTO A TAPE DRIVE. O ÍANDATORY ÍESSAGES: ÔHE LIST OF MANDATED MESSAGES HAS GROWN: +----------------------+--------------------------+-------------------+ Ý ÂOTH Ý ÔARGET Ý ÉNITIATOR Ý +----------------------+--------------------------+-------------------Ý Ý ÉDENTIFY Ý ÁBORT Ý ÄISCONNECT Ý Ý Ý Ý Ý Ý ÍESSAGE ÒEJECT Ý ÎO ÏPERATION Ý ÒESTORE ÐOINTER Ý Ý Ý Ý Ý Ý ÍESSAGE ÐARITY ÅRROR Ý ÂUS ÄEVICE ÒESET Ý ÓAVE ÄATA ÐOINTER Ý Ý Ý Ý Ý Ý Ý ÉNITIATOR ÄETECTED ÅRROR Ý Ý +----------------------+--------------------------+-------------------+ O ÏPTIONAL MESSAGES HAVE BEEN ADDED TO NEGOTIATE WIDE TRANSFERS AND ÔAGS TO SUPPORT COMMAND QUEUEING. Á LAST-MINUTE INCLUSION IN ÓÃÓÉ-2 WAS THE ABILITY TO ÔERMINATE É/Ï AND RECEIVE THE RESIDUE INFORMATION IN ÃHECK ÃONDITION STATUS (SO THAT ONLY THE INCOMPLETE PART OF THE COMMAND NEED BE RE-STARTED BY THE INITIATOR). O ÃOMMAND ÑUEUEING: ÉN ÓÃÓÉ-1, INITIATORS WERE LIMITED TO ONE COMMAND PER ÌÕÎ E.G. A DISK DRIVE. ÎOW UP TO 256 COMMANDS CAN BE OUTSTANDING TO ONE ÌÕÎ. ÔHE TARGET IS ALLOWED TO RE-SEQUENCE THE ORDER OF COMMAND EXECUTION TO OPTIMIZE SEEK MOTIONS. ÑUEUED COMMANDS REQUIRE ÔAG MESSAGES WHICH FOLLOW THE ÉDENTIFY. O ÄISK ÃACHEING: ÔWO CONTROL BITS ARE USED IN THE ÃÄ (ÃOMMAND ÄESCRIPTOR ÂLOCK) TO CONTROL WHETHER THE CACHE IS ACCESSED ON A ÒEAD OR ×RITE COMMAND, AND SOME COMMANDS HAVE BEEN ADDED TO CONTROL PRE-FETCHING AND LOCKING OF DATA INTO THE CACHE. ÕSERS DO NOT HAVE TO CHANGE THEIR SOFTWARE TO TAKE ADVANTAGE OF CACHEING, HOWEVER, AS THE ÍODE ÓELECT/ÍODE ÓENSE ÃACHE PAGE ALLOWS PARAMETERS TO BE SET WHICH OPTIMIZE THE ALGORITHMS USED IN THE TARGET TO MAXIMIZE CACHE PERFORMANCE. ÈERE IS ANOTHER AREA IN WHICH IMPROVEMENTS HAVE ALREADY BEEN PROPOSED IN ÓÃÓÉ-3, AND WILL TURN UP IN ÓÃÓÉ-2 PRODUCTS SHIPPING LATER THIS YEAR. O ÓENSE ËEYS AND ÓENSE ÃODES HAVE BEEN FORMALIZED AND EXTENDED. Á SUBSCRIPT BYTE TO THE ÓENSE ÃODE HAS BEEN ADDED TO PROVIDE SPECIFICS ON THE TYPE OF ERROR BEING REPORTED. ÁLTHOUGH OF LITTLE VALUE TO ERROR RECOVERY, THE ADDITIONAL INFORMATION ABOUT ERROR CAUSES IS USEFUL TO THE ENGINEER WHO HAS TO ANALYZE FAILURES IN THE FIELD, AND CAN BE USED BY HOST SYSTEMS AS INPUT TO PROGNOSTIC ANALYSIS TO ANTICIPATE FAULT CONDITIONS. O ÃOMMANDS: ÍANY OLD COMMANDS HAVE BEEN REWORKED AND SEVERAL NEW COMMANDS HAVE BEEN ADDED. O ÐAGES: ÓOME METHOD HAD TO BE FOUND TO PASS PARAMETERS BETWEEN HOST AND TARGET, AND THE TECHNIQUE USED IS KNOWN AS PAGES. ÔHE CONCEPT WAS INTRODUCED IN ÃÃÓ AND HAS BEEN EXPANDED MIGHTILY IN ÓÃÓÉ-2. Á NUMBER OF NEW ÃOMMON ÃOMMANDS HAVE BEEN ADDED, AND THE OPCODE SPACE FOR 10-BYTE ÃÄÂS HAS BEEN DOUBLED. O ÃHANGE ÄEFINITION ALLOWS A ÓÃÓÉ-2 INITIATOR TO INSTRUCT A ÓÃÓÉ-2 TARGET TO STOP EXECUTING ACCORDING TO THE 1986 STANDARD, AND PROVIDE ADVANCED ÓÃÓÉ- 2 FEATURES. ÍOST ÓÃÓÉ-2 TARGETS WILL POWER ON AND OPERATE ACCORDING TO THE 1986 STANDARD (SO THAT THERE IS NO RISK OF "DISTURBING" THE INSTALLED INITIATORS, AND WILL ONLY BEGIN OPERATING IN ÓÃÓÉ-2 MODE, OFFERING ACCESS TO THE ADVANCED ÓÃÓÉ-2 CAPABILITIES, AFTER BEING INSTRUCTED TO DO SO BY THE INITIATOR USING THE ÃHANGE ÄEFINITION COMMAND. O ÔHE ÍODE ÓELECT AND ÍODE ÓENSE PAGES WHICH DESCRIBE PARAMETERS FOR OPERATION HAVE BEEN GREATLY EXPANDED, FROM PRACTICALLY NOTHING IN 1986 TO HUNDREDS OF ITEMS IN ÓÃÓÉ-2. ×HENEVER YOU HEAR OF SOMETHING BEING DESCRIBED AS POWERFUL AND FLEXIBLE TOOL, THINK COMPLICATED. ÉNTEGRATORS ARE ADVISED TO BE JUDICIOUS IN THEIR SELECTION OF THE PAGES THEY DECIDE TO SUPPORT. O THE ÉNQUIRY COMMAND NOW PROVIDES ALL SORTS OF INTERESTING DATA ABOUT THE TARGET AND ITS ÌÕÎS. ÓOME OF THIS IS FIXED BY THE STANDARD, BUT THE MAIN BENEFIT MAY BE IN THE ÖENDOR ÕNIQUE DATA SEGREGATED INTO THE SPECIAL DESIGNATION OF ÖITAL ÐRODUCT ÄATA, WHICH CAN BE USED BY INTEGRATORS AS A TOOL TO MANAGE THE SYSTEM ENVIRONMENT. O ÓELECT ÌOG AND ÓENSE ÌOG HAVE BEEN ADDED SO THAT THE INITIATOR CAN GATHER BOTH HISTORICAL (E.G. ALL ÃHECK ÃONDITIONS) AND STATISTICAL (E.G. NUMBER OF SOFT ERRORS REQUIRING ÅÃÃ) DATA FROM THE TARGET. O ÄIAGNOSTIC CAPABILITIES HAVE BEEN EXTENDED ON THE ÒEAD/×RITE ÂUFFER AND ÒEAD/×RITE ÌONG COMMANDS. ÔHE WAYS IN WHICH THE TARGET CAN MANAGE BAD BLOCKS IN THE USER DATA SPACE HAVE BEEN DEFINED FURTHER AND REGULATED TO REDUCE INCONSISTENCIES IN THE 1986 STANDARD. Á COMPANION CAPABILITY TO ÒEAD ÄEFECT ÄATA PERMITS THE INITIATOR TO USE A STANDARD METHOD TO BE ADVISED OF DRIVE DEFECT LISTS. O Á NEW GROUP OF 12-BYTE COMMAND BLOCKS HAS BEEN DEFINED FOR ALL OPTICAL DEVICES TO SUPPORT THE LARGE VOLUME SIZES AND POTENTIALLY LARGE TRANSFER LENGTHS. ÔHE ÅRASE COMMAND HAS BEEN ADDED FOR REWRITABLE OPTICAL DISKS SO THAT AREAS ON THE MEDIA CAN BE PRE-ERASED FOR SUBSEQUENT RECORDING. ×RITE ÏNCE DISKS NEED ÍEDIA ÓCAN, SO THAT THE USER CAN FIND BLANK AREAS ON THE MEDIA. O ÎEW COMMAND SETS HAVE BEEN ADDED FOR ÓCANNERS, ÍEDIUM ÃHANGERS, AND ÃÄ ÒÏÍS. ÁLL OF THIS TECHNICAL DETAIL CAN GET BORING, SO HOW ABOUT SOME "GOODIES" IN ÓÃÓÉ-2 WHICH BENEFIT THE COMMON MAN AND HELP THE STRUGGLING ENGINEER? ÆIRST, AND PROBABLY THE BEST FEATURE IN ÓÃÓÉ-2 IS THAT THE DOCUMENT HAS BEEN ALPHABETIZED. ÎO LONGER DO YOU HAVE TO EMBARK ON A HUNT FOR THE ÒEAD COMMAND BECAUSE YOU CANNOT REMEMBER THE OPCODE. ÉN THE 1986 STANDARD, EVERYTHING WAS IN NUMERIC SEQUENCE, AND THE ONLY ENGINEERS WHO COULD FIND THINGS EASILY WERE THE MICROPROGRAMMERS WHO HAD MEMORIZED ALL THE MESSAGE AND OPCODE TABLES. ÎOW, ORDINARY PEOPLE CAN FIND THE ÒEAD COMMAND BECAUSE IT IS IN ALPHABETIC SEQUENCE. ÔHIS REORGANIZATION MAY SOUND LIKE A SMALL MATTER BUT IT WASN'T, IT REQUIRED A CONSIDERABLE AMOUNT OF EFFORT ON THE PART OF THE ÓÃÓÉ-2 EDITORS. ÉT WAS WELL WORTH IT. ÁNOTHER BOON IS THE INTRODUCTION FOR EACH DEVICE CLASS OF MODELS WHICH DESCRIBE THE DEVICE CLASS CHARACTERISTICS. ÔHE TAPE MODEL WAS THE MOST NEEDED, BECAUSE VARIOUS TAPE DEVICES USE THE SAME ACRONYM BUT WITH DIFFERENT MEANINGS OR DIFFERENT ACRONYMS FOR THE SAME MEANING. ÔHE ÓÃÓÉ-2 TAPE MODEL DEFINES THE TERMS USED BY ÓÃÓÉ-2, AND HOW THEY CORRESPOND TO THE ACRONYMS OF THE DIFFERENT TAPES. ÆOR EXAMPLE, ON A 9-TRACK REEL, ÅND OF ÔAPE IS A WARNING, AND THERE IS SUFFICIENT MEDIA BEYOND THE REFLECTIVE SPOT TO RECORD MORE DATA AND A TRAILER. ÎOT SO ON A 1/4" TAPE CARTRIDGE, ÅND OF ÔAPE MEANS OUT OF MEDIA AND NO MORE DATA CAN BE WRITTEN. ÔHIS SORT OF DIFFERENCE IN TERMS CAUSES NIGHTMARES FOR STANDARDIZATION EFFORTS. ÓO THERE IT IS, A SUMMARY OF WHAT IS IN ÓÃÓÉ-2. ÉT'S NOT SCARY, ALTHOUGH IT IS DAUNTING TO IMAGINE PLOWING THROUGH A 600-PAGE DOCUMENT. ÔIME FOR A COMMERCIAL HERE. ÔHE "ÓÃÓÉ ÂENCH ÒEFERENCE" AVAILABLE FROM ÅÎÄÌ ÐUBLICATIONS (408-867-6642), IS A COMPACTION OF THE STANDARD. ÉT TAKES THE 10% OF ÓÃÓÉ-2 WHICH IS CONSTANTLY REFERENCED BY ANY IMPLEMENTOR, AND PUTS IT IN AN EASY- TO-USE REFERENCE FORMAT IN A SMALL HANDBOOK. ÔHE AUTHOR IS ÊEFF ÓTAI, ONE OF THE EARLIEST ENGINEERS TO BECOME INVOLVED WITH ÓÃÓÉ IMPLEMENTATION, AND A SIGNIFICANT CONTRIBUTOR TO THE DEVELOPMENT OF BOTH THE 1986 STANDARD AND ÓÃÓÉ-2. ÓÃÓÉ-2 IS NOT YET PUBLISHED AS A STANDARD, BUT IT WILL BE AVAILABLE LATER THIS YEAR. ÕNTIL THEN, THE LATEST REVISION CAN BE PURCHASED FROM ÇLOBAL ÅNGINEERING (800-854-7179). ÂIOGRAPHY ÃONSULTANT AND ANALYST É. ÄAL ÁLLAN IS THE FOUNDER OF ÅÎÄÌ AND PUBLISHER OF THE ÅÎÄÌ ÌETTER AND THE "ÓÃÓÉ ÂENCH ÒEFERENCE." Á PIONEER AND ACTIVIST IN THE DEVELOPMENT AND USE OF STANDARD INTERFACES, HE IS ÖICE ÃHAIRMAN OF ÁÓà Ø3Ô9.2 (ÓÃÓÉ) AND ÃHAIRMAN OF THE ÓÃÓÉ-2 ÃOMMON ÁCCESS ÍETHOD ÃOMMITTEE. ==== ÑÕÅÓÔÉÏÎ: ÉS ÓÙÎÃÈÒÏÎÏÕÓ FASTER THAN ÁÓÙÎÃÈÒÏÎÏÕÓ? ÑÕÅÓÔÉÏÎ: ÉS THE 53Ã90 ÆASTER THAN SPEC? ÆROM: KSTEWART@NCR-MPD.ÆTÃOLLINS.ÎÃÒ.ÃÏÍ (ËEN ÓTEWART) ==== É'VE SEEN A FEW COMMENTS ABOUT OUR 54Ã90 BEING FASTER THAN SPEC. ×HILE É DOUBT THE AUTHOR WAS REALLY COMPLAINING (É GOT TWICE AS MUCH AS É PAID FOR--SURE MAKES ME MAD ;) É'D LIKE TO EXPLAIN THE SITUATION. ÁLONG THE WAY, É'LL ALSO SHOW THAT ASYNCHRONOUS IS FASTER ON SHORT CABLES, WHILE SYNCHRONOUS IS FASTER ON LONG CABLES. ÔHE CROSS-OVER POINT OCCURS SOMEWHERE AROUND SIX FEET--ASSUMING THAT YOU HAVE OUR 53Ã90 FAMILY DEVICES AT BOTH ENDS OF THE CABLE. ÔHE REASON HAS TO DO WITH THE PROPAGATION DELAY OF THE CABLE; THE TURN AROUND TIME OF THE SILICON; AND THE INTERLOCKED NATURE OF THE ASYNCHRONOUS HANDSHAKE. 1) ×E HAVE MEASURED PROPAGATION DELAYS FROM VARIOUS CABLES AND FOUND AN AVERAGE OF 1.7 NANOSECONDS PER FOOT, WHICH IS ROUGHLY 5.25 NS PER METER. 2) ÔHE TURN-AROUND TIME IS THE AMOUNT OF TIME THE ÓÃÓÉ CHIP TAKES TO CHANGE AN OUTPUT IN RESPONSE TO AN INPUT. ÉF ÒÅÑ IS AN INPUT THEN ÁÃË IS AN OUTPUT. ÏR IF ÁÃË IS AN INPUT THEN ÒÅÑ IS AN OUTPUT. ÔYPICAL TURN-AROUND TIME FOR THE 53Ã90 IS 40 NANOSECONDS. 3) ÔHE ASYNCHRONOUS TRANSFER USES AN INTERLOCKED HANDSHAKE WHERE A DEVICE CANNOT DO THE NEXT THING UNTIL IT RECEIVES POSITIVE ACKNOWLEDGMENT THAT THE OTHER DEVICE RECEIVED THE LAST THING. ÆIRST ÒÅÑ GOES TRUE /* DRIVEN BY ÔARGET */ THEN ÁÃË IS PERMITTED TO GO TRUE /* DRIVEN BY ÉNITIATOR */ THEN ÒÅÑ IS PERMITTED TO GO FALSE THEN ÁÃË IS PERMITTED TO GO FALSE ÔHUS WE HAVE FOUR "EDGES" PROPAGATING DOWN THE CABLE PLUS 4 TURN-AROUND DELAYS. ÁSYNCHRONOUS TRANSFER REQUIRES 55 NS SETUP AND NO HOLD TIME (PARAGRAPH IN 5.1.5.1 IN ÓÃÓÉ-1 OR ÓÃÓÉ-2) WHICH GIVES AN UPPER SPEED LIMIT AROUND 18 ÍÂ/S. Á DETAILED ANALYSIS (ASSUMING 53Ã90 FAMILY) SHOWS THAT THE SETUP TIME SUBTRACTS OUT. ÔHIS IS MOSTLY BECAUSE WE ARE RUNNING AT ONE-THIRD THE MAX RATE, BUT ALSO BECAUSE SETUP FOR THE NEXT BYTE CAN BEGIN ANYTIME AFTER ÁÃË IS RECEIVED TRUE OR ÒÅÑ IS RECEIVED FALSE, DEPENDING ON WHO IS RECEIVING. ÙOU CAN EITHER TAKE MY WORD FOR IT OR DRAW THE WAVEFORMS YOURSELF. ÔHUS, THE ASYNCHRONOUS TRANSFER REDUCES TO: (4 * 1.7 * 1) + (4 * 40NS) = 167 NS /* 1 FOOT CABLE */ = 6 ÍÂ/S (4 * 5.25 * 6) + (4 * 40NS) = 286 NS /* 6 METER CABLE */ = 3.5 ÍÂ/S (4 * 5.25 * 25) + (4 * 40NS) = 685 NS /* 25 METER CABLE */ = 1.5 ÍÂ/S NOTE: CABLES LONGER THAN 6 METERS REQUIRE EXTERNAL DIFFERENTIAL TRANSCEIVERS WHICH ADD DELAY AND DEGRADE THE PERFORMANCE EVEN MORE THAN INDICATED HERE. ÏUR SIMULATIONS SAY THAT UNDER VERY BEST CONDITIONS (FAST SILICON, LOW TEMPERATURE, HIGH VOLTAGE, ZERO LENGTH CABLE) WE CAN EXPECT MORE THAN 8 ÍÂ/S ASYNCHRONOUSLY. ÉN THE LAB, É ROUTINELY MEASURE 5 ÍÂ/S ON 8 FOOT CABLES. ÓO, IF YOU WERE WRITING THE DATA MANUAL FOR THIS, HOW WOULD ÙÏÕ SPEC IT? ÔHE FRAMERS OF THE ÓÃÓÉ SPEC THREW IN SYNCHRONOUS MODE TO BOOST THE PERFORMANCE ON LONG CABLES. ÉN SYNCHRONOUS MODE, THE SENDING DEVICE IS PERMITTED TO SEND THE NEXT BYTE WITHOUT RECEIVING ACKNOWLEDGMENT THAT THE RECEIVER ACTUALLY RECEIVED THE LAST BYTE. ËIND OF A SHIP AND PRAY METHOD. ÔHE ACKNOWLEDGMENT IS REQUIRED TO COME BACK SOMETIME, BUT WE JUST DON'T HAVE TO WAIT FOR IT (HANDWAVE THE OFFSET STUFF AND THE ENDING BOUNDARY CONDITIONS). ÉN THIS MODE ANY EXTERNAL TRANSCEIVERS ADD A TIME SHIFT, BUT NOT A DELAY. ÓO IF YOU NEGOTIATE FOR 5 ÍÂ/S, YOU GET 5ÍÂ/S REGARDLESS HOW LONG THE CABLE IS AND REGARDLESS WHETHER YOU ARE SINGLE-ENDED OR DIFFERENTIAL. ÂUT YOU CAN'T GO FASTER THAN 5.5 ÍÂ/S, EXCEPT IN ÓÃÓÉ-2. ÓYNCHRONOUS MODE DOES HAVE A HOLD TIME (UNLIKE ASYNCH) BUT AGAIN, SETUP AND HOLD TIMES SUBTRACT OUT. ÉN ÓÃÓÉ-1 SYNCHRONOUS MODE, THE SPEED LIMIT COMES FROM THE COMBINED ÁÓÓÅÒÔÉÏÎ ÐÅÒÉÏÄ + ÎÅÇÁÔÉÏÎ ÐÅÒÉÏÄ WHICH IS 90NS + 90NS = 180NS = 5.5 ÍÂ/S. ÏUR 53Ã90 FAMILY DOESN'T QUITE HIT THE MAX, BUT WE DO GUARENTEE 5.0 ÍÂ/S. ÉN ÓÃÓÉ-2, ANYTHING ABOVE 5.0 ÍÂ/S IS CONSIDERED TO BE ÆÁÓÔ. ÈERE THE MAXIMUM TRANSFER RATE IS EXPLICITLY LIMITED TO 100 NS OR 10ÍÂ/S; YOU DON'T HAVE TO READ BETWEEN THE LINES TO DEDUCE IT. ÉNTERESTING TID-BIT: GIVEN A ÓÃÓÉ-2 ÆÁÓÔ PERIOD OF 100 NS AND A CABLE DELAY OF 131 NS ON A 25 METER CABLE, YOU CAN ACTUALLY STACK 1.31 BYTES IN THE 8-BIT CABLE. ÉN ÆÁÓÔ AND ×ÉÄÅ ÓÃÓÉ YOU CAN STACK 5.24 BYTES IN THIS COPPER ÆÉÆÏ. ÈUMMM... ==== ÑÕÅÓÔÉÏÎ: ×HAT ARE THE JUMPERS ON MY ÃONNER DRIVE? ÁÎÓ×ÅÒ ÆROM: EKRIEGER@QUASAR.HACKTIC.NL (ÅRIC ËRIEGER) ÅMBELLISHMENT FROM: ÈENRIK ÓTAHL (F92-HST@NADA.KTH.SE) ==== ÑÕÉÃË ÉÎÓÔÁÌÌÁÔÉÏÎ ÇÕÉÄÅ ÓÃÓÉ ÍOST ÓÃÓÉ HOST ADAPTERS ARE COMPATIBLE WITH ÃONNER DRIVES. ÓOFTWARE DRIVERS AND INSTALLATION INSTRUCTIONS ARE PROVIDED WITH THE HOST ADAPTER. ÔHE DRIVES ARE SHIPPED WITH ÓÃÓÉ ÉÄ SET TO 7. ÔO SELECT A DIFFERENT ÉÄ REFER TO THE FOLLOWING: ÔABLE Á ÔABLE  ÉÄ Å-1 Å-2 Å-3 ÉÄ Å2 Å3 Å4 0 OUT OUT OUT 0 OUT OUT OUT 1 IN OUT OUT 1 IN OUT OUT 2 OUT IN OUT 2 OUT IN OUT 3 IN IN OUT 3 IN IN OUT 4 OUT OUT IN 4 OUT OUT IN 5 IN OUT IN 5 IN OUT IN 6 OUT IN IN 6 OUT IN IN 7 IN IN IN 7 IN IN IN ÐARITY IS ALWAYS ÅÎÁÂÌÅÄ ON THE ÃÐ3200,ÃÐ30060,ÃÐ30080,ÃÐ30100, ÃÐ 30200, ÃÐ 3500, ÃÐ 3360, ÃÐ 30540 AND ÃÐ 31370. ÆOR THE ÃÐ 340, JUMPER Å-1 TO DISABLE PARITY. ÁLL OTHER MODELS, JUMPER Å-4 TO DISABLE PARITY. ÓÃÓÉ DRIVE PARAMETERS: ÍODEL ÈDS ÃYL ÓEC ÔABLE ÌÅÄ ÃÐ2020 2 642 32 Á N/A ÃÐ340 4 788 26  1 ÃÐ3020 2 622 33 Á 1 ÃÐ3040 2 1026 40 Á 1 ÃÐ3180 6 832 33 Á 1 ÃÐ3100 8 776 33 Á 1 ÃÐ30060 2 1524 39 Á 2 ÃÐ30080 4 1053 39 Á 2 ÃÐ30100 4 1522 39 Á 2 ÃÐ30200 4 2119 49 Á 2 ÃÐ3200 8 1366 38 Á 2 ÃÐ3360 8 1806 49 Á 2 ÃÐ3540 12 1806 49 Á 2 ÃÐ 30080Å 2 1806 46 ÁÁ Ã/Å ÃÐ 30170Å 4 1806 46 ÁÁ Ã/Å ÃÐ 30540 6 2249 59-89 ÁÁ  ÃÐ 31370 14 2094 59-95 ÁÁ  ÌÅÄ 1 ÌÅÄ 2 Ê-4 ÐIN 1 = + Ê-1 ÐIN 3 = + ÐIN 2 = - ÐIN 4 = - ÏN THE ÃÐ 31370, JUMPER Å5 ENABLES TERMINATION. ÄEFAULT IS TERMINATION ON. ÉT MAY BE THE SAME JUMPER FOR OTHER MODELS. ==== ÑÕÅÓÔÉÏÎ: ×HAT ARE THE JUMPERS FOR MY ×ANGTEK 5150 DRIVE? ÁÎÓ×ÅÒ ÆROM: "ÔERRY ËENNEDY, ÏPERATIONS ÍGR" ==== ÆIRST, THE DISCLAIMER: ÔHIS IS NOT AN OFFICIAL REPRESENTATION OF ×ANGTEK OR OF MY EMPLOYER. ÔHIS IS INFO É'VE DISCOVERED BY READING PUBLICLY AVAIL- ABLE REFERENCE MATERIAL. ×HEN CHANGING JUMPERS, ALWAYS OBSERVE PROPER ANTI- STATIC PRECAUTIONS AND BE SURE YOU HAVE THE CURRENT CONFIGURATION WRITTEN DOWN SO YOU HAVE A KNOWN STARTING POINT. ÏK. ÈERE'S THE COMPLETE SCOOP ON ×ANGTEK 5150ÅÓ DRIVES: ÔHE CURRENT PART NUMBER FOR A "GENERIC" 5150ÅÓ IS: 33685-201 (BLACK FACEPLATE) 33685-202 (BEIGE FACEPLATE) ÔHESE ARE REFERRED TO AS THE "ÁÃÁ VERSION" OF THE DRIVE. ÔHERE ARE ßMANYß OTHER PART NUMBERS FOR 5150ÅÓ DRIVES. ÉF YOU HAVE ONE THAT ISN'T ONE OF THE ABOVE, IT DOESN'T MEAN YOU HAVE AN OLD OR AN OUT OF REV DRIVE, IT JUST MEANS IT'S A SPECIAL VERSION CREATED FOR A DISTRIBUTOR OR ÏÅÍ, OR WITH DIFFERENT DEFAULT JUMPER SETTINGS. ÙOU CAN ORDER THE ×ANGTEK 5150ÅÓ ÏÅÍ ÍANUAL FROM ×ANGTEK. ÉT IS PART NUMBER 63045-001 ÒEVISION Ä. ÔHERE ARE 5 POSSIBLE LOGIC BOARDS. ÈERE ARE THE JUMPER OPTIONS FOR EACH: ÌOGIC ASSEMBLY #33678 --------------------- (Ê10) 0 - ÓÃÓÉ UNIT ÌÓ 1 - ÓÃÓÉ UNIT 2 - ÓÃÓÉ UNIT ÍÓÂ Ë - NOT DOCUMENTED Ê32 - ÄIAGNOSTIC TEST CONNECTOR, DEFAULT IS NOT INSTALLED Å1, Æ1 - ÓÃÓÉ TERMINATION POWER. Å1 IN = POWER FROM DRIVE AND TO CABLE, Å1 OUT - POWER FROM CABLE. Æ1 = TERMINATOR POWER FUSE, 1.5Á ÆÂ. ÄEFAULT IS ÉÎ. Å2 - ÃHASSIS GROUND. Å2 IN JUMPERS LOGIC TO CHASSIS GROUND. Å2 OUT ISOLATES THROUGH A .33 UÆÄ CAPACITOR. ÄEFAULT IS ÉÎ. Å5 - ÍASTER OSCILLATOR ENABLE. ÔEST ONLY. ÍUST BE ÉÎ. Å20 - ÆACTORY TEST. ÍUST BE ÏÕÔ. ÒÐ1, ÒÐ2, ÒÐ3 - ÓÉÐ TERMINATORS. ÄEFAULT IS ÉÎ, REMOVE FOR NO TERMINATION. ÌOGIC ASSEMBLY #30559 --------------------- ÈÄÒ1 - ÆACTORY TESTING. ÓETTING DEPENDS ON DRIVE. ÄON'T TOUCH. ÈÄÒ2 - ÆACTORY TESTING. ÄEFAULTS ARE PINS 15-16, 17-18, 19-20. ÄON'T TOUCH. ÈÄÒ3 PIN 1 - Á- ENABLES BUFFERED MODE. Â-à DISABLES. ÃAN BE OVERRIDDEN BY ÓÃÓÉ ÍODE ÓELECT. ÈÄÒ3 PIN 2, 3 - ÄEFAULT DATA FORMAT. ÓET TO Â-à FOR A 5150ÅÓ. ÈÄÒ3 PIN 4 - PARITY ENABLE. Á- ENABLES, Â-à DISABLES. (Ê10) 0 - ÓÃÓÉ UNIT ÌÓ 1 - ÓÃÓÉ UNIT 2 - ÓÃÓÉ UNIT ÍÓÂ Ë - NOT DOCUMENTED Å1 - ÓÃÓÉ TERMINATION POWER. Å1 IN = POWER FROM DRIVE AND TO CABLE, Å1 OUT - POWER FROM CABLE. Å2 - ÃHASSIS GROUND. Å2 IN JUMPERS LOGIC TO CHASSIS GROUND. Å2 OUT ISOLATES THROUGH A .33 UÆÄ CAPACITOR. ÄEFAULT IS ÉÎ. Å3 - ÍASTER OSCILLATOR ENABLE. ÔEST ONLY. ÍUST BE ÉÎ. Å4 - ×RITE TEST MODE. ÔEST ONLY. ÍUST BE ÏÕÔ. Å5 - ×RITE OSCILLATOR ENABLE. ÔEST ONLY. ÍUST BE ÉÎ. Å6 - ÄISABLE ÈÄÒ2. ÔEST ONLY. ÍUST BE ÉÎ. Å7 - ÍICROCONTROLLER CLOCK SELECT. ÉN FOR A 5150ÅÓ. Å8 - ×RITE PRECOMP SELECT. ÓET ON A PER-DRIVE BASIS. ÄON'T TOUCH. Å9 - ÒÁÍ SIZE. ÄON'T TOUCH. Å10 - ÅRASE FREQUENCY. ÄON'T TOUCH. ÒÐ2, ÒÐ3 - ÄÉÐ AND ÓÉÐ TERMINATORS. ÄEFAULT IS ÉÎ, REMOVE FOR NO TERMINATION. ÌOGIC ASSEMBLY #30600 --------------------- ÈÄÒ1 - ÆACTORY TESTING. ÓETTING DEPENDS ON DRIVE. ÄON'T TOUCH. ÈÄÒ2 - ×RITE PRECOMP SELECT. ÓET ON A PER-DRIVE BASIS. ÄON'T TOUCH. ÈÄÒ3 PIN 1, 2, 3 - ÓÃÓÉ DEVICE ADDRESS. 1 IS ÌÓÂ, 3 IS ÍÓÂ. Á-Â=1, Â-Ã=0 ÈÄÒ3 PIN 4 - ÐARITY ENABLE. ÉÁ- IS ENABLED. ÈÄÒ3 PIN 5, 6 - ÄEFAULT DATA FORMAT. Â-à FOR A 5150ÅÓ. ÈÄÒ3 PIN 7 - ÂUFFERED MODE SELECT. Á- IS ENABLED. ÈÄÒ3 PIN 8 - ÒESERVED. ÍUST BE ÏÕÔ. ÈÄÒ4 - ×RITE FREQUENCY SELECT. ÄON'T TOUCH. Å1 - ÓÃÓÉ TERMINATION POWER. Å1 IN = POWER FROM DRIVE AND TO CABLE, Å1 OUT - POWER FROM CABLE. Å2 - ÃHASSIS GROUND. Å2 IN JUMPERS LOGIC TO CHASSIS GROUND. Å2 OUT ISOLATES THROUGH A .33 UÆÄ CAPACITOR. ÄEFAULT IS ÉÎ. Å3 - ÈARD/SOFT RESET. ÉÎ ENABLES HARD RESET. Å4 - ×RITE PRECOMP SELECT. ÄON'T TOUCH. Å5 - ÃLOCK SPEED. ÄON'T TOUCH. Å6 - ÔAPE HOLE TEST. ÄON'T TOUCH. ÌOGIC ASSEMBLY #30552 --------------------- ÈÄÒ1 - ÆACTORY TESTING. ÓETTING DEPENDS ON DRIVE. ÄON'T TOUCH. ÈÄÒ2 - ×RITE PRECOMP SELECT. ÓET ON A PER-DRIVE BASIS. ÄON'T TOUCH. ÈÄÒ3 PIN 1, 2, 3 - ÓÃÓÉ DEVICE ADDRESS. 1 IS ÌÓÂ, 3 IS ÍÓÂ. [ÎOTE - ÈÄÒ3 PINS 1-3 ARE DUPLICATED AT ANOTHER LOCATION ON THE BOARD] ÈÄÒ3 PIN 4 - ÐARITY ENABLE. ÉÎ IS ENABLED. ÈÄÒ3 PIN 5, 6, 7, 8 - ÄEFAULT DATA FORMAT. 5,5 Â-Ã, 7-8 Á- FOR A 5150ÅÓ. ÈÄÒ4 - ×RITE FREQUENCY SELECT. ÄON'T TOUCH. Å1 - ÓÃÓÉ TERMINATION POWER. Å1 IN = POWER FROM DRIVE AND TO CABLE, Å1 OUT - POWER FROM CABLE. Å2 - ÃHASSIS GROUND. Å2 IN JUMPERS LOGIC TO CHASSIS GROUND. Å2 OUT ISOLATES THROUGH A .33 UÆÄ CAPACITOR. ÄEFAULT IS ÉÎ. Å3 - ÈARD/SOFT RESET. ÉÎ ENABLES HARD RESET. Å4 - ×RITE PRECOMP SELECT. ÄON'T TOUCH. Å5 - ÃLOCK SPEED. ÄON'T TOUCH. Å6 - ÔAPE HOLE TEST. ÄON'T TOUCH. ÌOGIC ASSEMBLY #30427 --------------------- ÈÄÒ1 - ÆACTORY TESTING. ÓETTING DEPENDS ON DRIVE. ÄON'T TOUCH. ÈÄÒ2 - ×RITE PRECOMP SELECT. ÓET ON A PER-DRIVE BASIS. ÄON'T TOUCH. ÈÄÒ3 PIN 1, 2, 3 - ÓÃÓÉ DEVICE ADDRESS. 1 IS ÌÓÂ, 3 IS ÍÓÂ. Á-Â=1, Â-Ã=0 ÈÄÒ3 PIN 4 - ÐARITY ENABLE. ÉÁ- IS ENABLED. ÈÄÒ3 PIN 5, 6, 7, 8 - ÄEFAULT DATA FORMAT. 5,5 Â-Ã, 7-8 Á- FOR A 5150ÅÓ. Å1, Å3 - ÆACTORY TEST. ÍUST BE ÉÎ. Å2 - ÓÃÓÉ TERMINATION POWER. Å2 IN = POWER FROM DRIVE AND TO CABLE, Å2 OUT - POWER FROM CABLE. Å4 - ÃHASSIS GROUND. Å4 IN JUMPERS LOGIC TO CHASSIS GROUND. Å4 OUT ISOLATES THROUGH A .33 UÆÄ CAPACITOR. ÄEFAULT IS ÉÎ. ÆIRMWARE - ÔHERE ARE MANY FLAVORS OF FIRMWARE. É HAVE SEEN THE FOLLOWING PARTS: 24115-XXX 24144-XXX 21158-XXX THE -XXX SUFFIX CHANGES AS THE FIRMWARE IS UPDATED. ÁCCORDING TO THE FOLKS É SPOKE TO AT ×ANGTEK, THE STANDARD FIRMWARE IS THE 21158. ÔHE LATEST VERSION AS OF THIS WRITING IS 21158-007. ÁLL OF THESE WILL WORK WITH THE ÁDAPTEC AND ÇÔÁË. ÔHE FIRMWARE OPTIONS (AS RETURNED BY A ÓÃÓÉ ÉDENTIFY) ARE ON THE END OF THE PRODUCT STRING, WHICH IS "×ÁÎÇÔÅË 5150ÅÓ ÓÃÓÉ ÅÓ41Ã560 ÁÆÄ ÑÆÁ ÓÔÄ" FOR THE 21158-007 FIRMWARE. ÔHE 3-LETTER CODES HAVE THE FOLLOWING MEANING: ÁÆÄ - ÁUTOMATIC ÆORMAT ÄETECTION - THE DRIVE WILL RECOGNIZE THE FORMAT (SUCH AS ÑÉÃ-24, ÑÉÃ-120, OR ÑÉÃ-150) THAT THE TAPE WAS WRITTEN IN. ÑÆÁ - ÑUICK ÆILE ÁCCESS - THE ABILITY TO RAPIDLY LOCATE A TAPE BLOCK, AND TO IMPLEMENT THE "POSITION TO BLOCK" AND "REPORT BLOCK" ÓÃÓÉ COMMANDS. ÔHIS IS COMPATIBLE WITH THE ÔANDBERG IMPLEMENTATION. ÓÔÄ - ÓTANDARD FEATURE SET. ==== ÑÕÅÓÔÉÏÎ: ×HAT IS ÃÁÍ? ÁÎÓ×ÅÒ ÆROM: CTJONES@BNR.CA (ÃLIFTON ÊONES) ==== ÃOMMON ÁCCESS ÍETHOD. ÉT IS A PROPOSED ÁÎÓÉ STANDARD TO MAKE IT EASIER TO PROGRAM ÓÃÓÉ APPLICATIONS BY ENCAPSULATING THE ÓÃÓÉ FUNCTIONS INTO A STANDARDIZED CALLING CONVENTION. ÁÎÓ×ÅÒ ÆROM: LANDIS@SUGS.TWARE.COM (ÈALE ÌANDIS) ==== ÙOU MAY BE ABLE TO GET THE ÃÁÍ SPEC(S) FROM THE ÓÃÓÉ ÂÂÓ ==== ÑÕÅÓÔÉÏÎ: ×HAT IS ÆÐÔ (ÔERMINATION)? ÁÎÓ×ÅÒ ÆROM: JVINCENT@BNR.CA (ÊOHN ÖINCENT) ==== ÆÐÔ IS ACTUALLY REALLY SIMPLE, É WISH É HAD THOUGHT OF IT. ×HAT IT DOES IS USE DIODE CLAMPS TO ELIMINATE OVER AND UNDERSHOOT. ÔHE "TRICK" IS THAT INSTEAD OF CLAMPING TO +5 AND ÇÎÄ THEY CLAMP TO THE OUTPUT OF TWO REGULATED VOLTAGES. ÔHIS ALLOWS THE CLAMPING DIODES TO TURN ON EARLIER AND IS THEREFORE BETTER AT ELIMINATING OVERSHOOT AND UNDERSHOOT. ÔHE BLOCK DIAGRAM FOR A ÆÐÔED SIGNAL IS BELOW. ÔHE RESISTOR VALUE IS PROBABLY IN THE 120 TO 130 OHM RANGE. ÔHE ACTUAL OUTPUT VOLTAGES OF THE REGULATORS MAY NOT BE EXACLTY AS É HAVE SHOWN THEM BUT IDEALLY THEY ARE MATCHED TO THE DIODE CHARACTERISTICS SO THAT CONDUCTION OCCURS WHEN THE SIGNAL VOLTAGE IS GREATER THAN 3.0 Ö OR LESS THAN 0.5 Ö. +--------------- ÔÅÒÍÐ×Ò Ý ßßßßÝßßßß Ý Ý Ý ÖREG 1 Ý-------*-------------------------*--------------- 3.? Ö ÝßßßßßßßßÝ Ý Ý Ý Ý Ý Ý Ý \ +------------* / PULLUP RESISTOR Ý Ý \ Ý Ý / Ý ßßßßÝßßß Ý Ý Ý Ý Ý Ý Ý ÖREG 2 Ý----------*----------Ý--------------- 3.0 Ö Ý ÝßßßßßßßßÝ Ý Ý Ý --+-- Ý Ý / \ Ý +-----------+ /ßßß\ Ý Ý Ý Ý Ý Ý Ý TERMINATED Ý *----------*------------- SIGNAL Ý Ý Ý Ý Ý --+-- Ý / \ Ý /ßßß\ Ý Ý ßßßÝßßßß Ý Ý Ý Ý Ý ÖREG 3 Ý----------*------------------------- 1.0 Ö (?) ÝßßßßßßßßÝ ==== ÑÕÅÓÔÉÏÎ: ×HAT IS ÁCTIVE ÔERMINATION? ÁÎÓ×ÅÒ ÆROM: ERIC@TELEBIT.COM (ÅRIC ÓMITH) AND BRENT@AUSPEX.COM (ÂRENT Ò. ÌARGENT) ==== ÁN ACTIVE TERMINATOR ACTUALLY HAS ONE OR MORE VOLTAGE REGULATORS TO PRODUCE THE TERMINATION VOLTAGE, RATHER THAN USING RESISTOR VOLTAGE DIVIDERS. ÔHIS IS A PASSIVE TERMINATOR: ÔÅÒÍÐ×Ò ------/\/\/\/------+------/\/\/\/----- ÇÎÄ Ý Ý ÓÃÓÉ SIGNAL ÎOTICE THAT THE TERMINATION VOLTAGE IS VARIES WITH THE VOLTAGE ON THE ÔÅÒÍÐ×Ò LINE. ÏNE VOLTAGE DIVIDER (TWO RESISTORS) IS USED FOR EACH ÓÃÓÉ SIGNAL. ÁN ACTIVE TERMINATOR LOOKS MORE LIKE THIS (SUPPLY FILTER CAPS OMITTED): +-----------+ ÔÅÒÍÐ×Ò -----Ý IN OUT Ý------+------/\/\/\/-------ÓÃÓÉ SIGNAL Ý GND Ý Ý +-----------+ Ý Ý +------/\/\/\/-------ÓÃÓÉ SIGNAL Ý Ý ÇÎÄ ---------------+ Ý +------/\/\/\/-------ÓÃÓÉ SIGNAL Ý ETC. ÁSSUMING THAT THE ÔÅÒÍÐ×Ò VOLTAGE DOESN'T DROP BELOW THE DESIRED TERMINATION VOLTAGE (PLUS THE REGULATOR'S MINIMUM DROP), THE ÓÃÓÉ SIGNALS WILL ALWAYS BE TERMINATED TO THE CORRECT VOLTAGE LEVEL. ÓEVERAL VENDORS HAVE STARTED MAKING ÓÃÓÉ ACTIVE TERMINATOR CHIPS, WHICH CONTAIN THE REGULATOR AND THE RESISTORS INCLUDING ÄALLAS ÓEMICONDUCTOR, ÕNITRODE ÉNTEGRATED ÃIRCUITS AND ÍOTOROLA ==== ÑÕÅÓÔÉÏÎ: ×HY ÉS ÁCTIVE ÔERMINATION ÂETTER? ÁÎÓ×ÅÒ BRENT@AUSPEX.COM (ÂRENT Ò. ÌARGENT) ==== ÔYPICAL PASIVE TERMINATORS (RESISTORS) FLUCTUATE DIRECTLY IN RELATION TO THE ÔÅÒÍ ÐOWER ÖOLTAGE. ÕSUALLY TERMINATING RESISTORS WILL SUFFICE OVER SHORT DISTANCES, LIKE 2-3 FEET, BUT FOR LONGER DISTANCES ACTIVE TERMINATION IS A REAL ADVANTAGE. ÉT REDUCES NOISE. ÁCTIVE ÔERMINATION PROVIDE NUMEROUS ADVANTAGES: - Á LOGIC BIT CAN DISCONNECT THE TERMINATION - ÐROVIDES ÎEGATIVE ÃLAMPING ON ALL SIGNAL LINES - ÒEGULATED TERMINATION VOLTAGE - ÓÃÓÉ-2 SPEC RECOMMENDS ACTIVE TERMINATION ON BOTH ENDS OF THE SCSI CABLE. - ÉMPROVED ÒESISTANCE TOLERENCES (FROM 1% TO ABOUT 3%) ==== ÑÕÅÓÔÉÏÎ: ×HY IS ÓÃÓÉ MORE EXPENSIVE THAN ÉÄÅ? ÁÎÓ×ÅÒ ÆROM: LANDIS@SUGS.TWARE.COM (ÈALE ÌANDIS) ==== ÉN A TYPICAL SINGLE DRIVE Ðà SYSTEM, ÁÔÁ (YOU CALL IT ÉÄÅ, THE PROPER NAME IS ÁÔÁ) IS FASTER THAN ANY ÓÃÓÉ. ÔHIS IS BECAUSE OF THE 1 TO 2 MILLISECOND COMMAND OVERHEAD OF A ÓÃÓÉ HOST ADAPTER VS. THE 100 TO 300 MICROSECOND COMMAND OVERHEAD OF AN ÁÔÁ DRIVE. ÁLSO, ÁÔÁ TRANSFERS DATA 16-BITS AT A TIME FROM THE DRIVE DIRECTLY TO/FROM THE SYSTEM BUS. ÃOMPARE THIS TO ÓÃÓÉ WHICH TRANSFERS DATA 8-BITS AT A TIME BETWEEN THE HOST ADAPTER AND THE DRIVE. ÔHE HOST ADAPTER MAY BE ABLE TO TRANSFER DATA 16-BITS AT A TIME TO THE SYSTEM BUS. ÏF COURSE YOU COULD GO TO ÆAST ÓÃÓÉ OR ×IDE ÓÃÓÉ BUT THAT COSTS A WHOLE BUNCH MORE! ÂUT THEN YOU ASKED ABOUT COST. ÔHE REAL REASON ÓÃÓÉ COSTS MORE HAS TO DO WITH PRODUCTION VOLUME. ÔHERE ARE ABOUT 120,000 DRIVES MADE PER DAY ON THIS PLANET. 85% OF THOSE DRIVES ARE ÁÔÁ. ÔHE REMAINDER ARE ÓÃÓÉ, ÉÐÉ, ÓÍÄ AND A FEW OTHER STRANGE INTERFACES. ÔHE ACTUAL PERCENT THAT ARE ÓÃÓÉ IS FALLING AT A VERY VERY SLOW RATE. ×ITHOUT THE PRODUCTION VOLUME, COMPONET PRICES ARE HIGHER, THEREFOR DRIVE PRICES ARE HIGHER. ÁND THEN YOU MUST ADD IN THE HOST ADAPTER COST. ÃOMPARE $15 FOR ÁÔÁ VS. $50 FOR A SIMPLE ÓÃÓÉ HOST ADAPTER. ÂUT YOU PROBABLY WANT A HIGHER QUALITY ÓÃÓÉ HOST ADAPTER SO PLAN ON SPENDING $100 TO $500 FOR ONE. ÙOU FIGURE OUT HOW TO GET PEOPLE TO BUY MORE ÓÃÓÉ DRIVES, SAY 50,000 PER DAY, AND MAYBE THE PRICES WILL COME DOWN TO ÁÔÁ PRICE LEVELS. ÐLUS YOU COULD PROBABLY GET A VERY GOOD MARKETING JOB AT ANY OF THE DISK DRIVE COMPANIES! ÏF COURSE, EACH DAY MORE AND MORE PEOPLE ARE DISCOVERING THE PERFORMANCE ADVANTAGE OF ÁÔÁ SO YOUR JOB MAY NOT BE AS EASY AS YOU WOULD LIKE. ==== ÑÕÅÓÔÉÏÎ: ×HAT IS ÐLUG AND ÐLAY ÓÃÓÉ? ÁÎÓ×ÅÒ: LEEFI@MICROSOFT.COM (ÌEE ÆISHER) (ÕPDATED ÄEC 7 1993) ==== ÐLUG AND ÐLAY IS THE NAME OF A TECHNOLOGY THAT LETS Ðà HARDWARE AND ATTACHED DEVICES WORK TOGETHER AUTOMATICALLY. Á USER CAN SIMPLY ATTACH A NEW DEVICE ("PLUG IT IN") AND BEGIN WORKING ("BEGIN PLAYING"). ÔHIS SHOULD BE POSSIBLE EVEN WHILE THE COMPUTER IS RUNNING, WITHOUT RESTARTING IT. ÐLUG AND ÐLAY TECHNOLOGY IS IMPLEMENTED IN HARDWARE, IN OPERATING SYSTEMS SUCH AS ÍICROSOFT ×INDOWS, AND IN SUPPORTING SOFTWARE SUCH AS DRIVERS AND ÂÉÏÓ. ×ITH ÐLUG AND ÐLAY TECHNOLOGY, USERS CAN EASILY ADD NEW CAPABILITIES TO THEIR ÐÃS, SUCH AS SOUND OR FAX, WITHOUT HAVING TO CONCERN THEMSELVES WITH TECHNICAL DETAILS OR ENCOUNTERING PROBLEMS. ÆOR USERS OF MOBILE ÐÃS (WHO ARE FREQUENTLY CHANGING THEIR CONFIGURATIONS WITH DOCKING STATIONS, INTERMITTENT NETWORK CONNECTIONS, ETC.) ÐLUG AND ÐLAY TECHNOLOGY WILL EASILY MANAGE THEIR CHANGING HARDWARE CONFIGURATION. ÆOR ALL USERS, ÐLUG AND ÐLAY WILL REDUCE THE TIME WASTED ON TECHNICAL PROBLEMS AND INCREASE THEIR PRODUCTIVITY AND SATISFACTION WITH ÐÃS. ÔHE ÐLUG AND ÐLAY TECHNOLOGY IS DEFINED IN A SERIES OF SPECIFICATIONS COVERING THE MAJOR COMPONENT PIECES. ÔHERE ARE SPECIFICATIONS FOR ÂÉÏÓ, ÉÓÁ CARDS, ÐÃÉ, ÓÃÓÉ, ÉÄÅ ÃÄ-ÒÏÍ, ÐÃÍÃÉÁ, DRIVERS, AND ÍICROCHANNEL. ÉN A NUTSHELL, EACH HARDWARE DEVICE MUST BE ABLE TO BE UNIQUELY IDENTIFIED, IT MUST STATE THE SERVICES IT PROVIDES AND THE RESOURCES WHICH IT REQUIRES, IT MUST IDENTIFY THE DRIVER WHICH SUPPORTS IT, AND FINALLY IT MUST ALLOW SOFTWARE TO CONFIGURE IT. ÔHE FIRST ÐLUG AND ÐLAY COMPLIANT PRODUCTS ARE AVAILABLE NOW, AS ARE DEVELOPMENT KITS FOR DRIVERS AND HARDWARE. ÔWENTY DIFFERENT ÐLUG AND ÐLAY PRODUCTS WERE SHOWN AT ÃOMDEX IN ÎOVEMBER 1993. ÓPECIFICATIONS: ÔHE ÐLUG AND ÐLAY SPECIFICATIONS ARE NOW AVAILABLE VIA ANONYMOUS FTP AT FTP.MICROSOFT.COM IN THE \DRG\PLUG-AND-PLAY SUBDIRECTORY. ÔHE FILES ARE COMPRESSED IN .ZIP FORMAT, AND ARE IN ÍICROSOFT ×ORD FORMAT.) ÐLUG AND ÐLAY ÉÓÁ FILES (.\PNPISA\*) ERRATA.ZIP ÃLARIFICATIONS AND CORRECTIONS TO PNPISA.DOC ISOLAT.ZIP ÍÓ-ÄÏÓ TESTING TOOL TO ISLOATE ÉÓÁ ÐNÐ HARDWARE PNPDOS.ZIP ÐLUG AND ÐLAY DEVICE DRIVER INTERFACE SPECIFICATION PNPISA.ZIP ÈARDWARE SPEC FOR ÐNÐ ÉÓÁ ENHANCEMENT VHDLZI.ZIP ÈARDWARE SPEC FOR ÐNÐ ÉÓÁ ENHANCEMENT ÐLUG AND ÐLAY ÓÃÓÉ FILES (.\SCSIßIDE\*): PNPSCSI.ZIP ÐLUG AND ÐLAY ÓÃÓÉ SPECIFICATION PROPOSAL SCAM.ZIP ÓÃÁÍ (ÓÃÓÉ ÃOMNFIGURED ÁUTO-ÍAGICALLY) SPECIFICATION ÐLUG AND ÐLAY ÂÉÏÓ FILES (.\BIOS\*): APMV11.ZIP ÁDVANCED ÐOWER MANAGEMENT SPEC V.1 VIOS.ZIP ÐLUG AND ÐLAY ÂÉÏÓ SPEC ESCD1.ZIP ÓPEC FOR OPTIONAL METHOD OF STORING CONFIG INFO FOR ÐNÐ ÂÉÏÓ ÐLAYÌIST@ÍICROSOFT.ÃÏÍ ALIAS: ÔHERE IS AN ALIAS, ÐLAYÌIST@ÍICROSOFT.ÃÏÍ, WHICH YOU CAN EMAIL AND GET ON A ÍICROSOFT MAILING LIST RELATED TO ÐLUG AND ÐLAY, WHERE THE ÈARDWARE ÖENDOR ÒELATIONS ÇROUP (ÈÖÒÇ) WILL MAIL OUT NEW SPECIFICATIONS, ANNOUNCEMENTS, INFORMATION ON WORKSHOPS, ×INDOWS ÈARDWWARE ÅNGINEERING ÃONFERENCE (×INÈÅÃ), ETC... ÃOMPUSERVE ÐLUGÐLAY FORUM: ÔHERE IS A FORUM ON ÃOMPUSERVE, ÇÏ ÐÌÕÇÐÌÁÙ. ÔHIS FORUM IS THE METHOD FOR SUPPORT, DISCUSSIONS AND DIALOGS ABOUT ÐLUG AND ÐLAY. ÉN ADDITION, THE FORUM'S LIBRARY CONTAINS ALL OF THE CURRENT SPECIFICATION. ÉNTEL ÐLUG AND ÐLAY KITS: ÉF YOU ARE INTERESTED IN ÉNTEL'S TWO ÐLUG AND ÐLAY KITS, EITHER "ÐLUG AND ÐLAY ËIT FOR ÍÓ-ÄÏÓ AND ×INDOWS" OR "ÐLUG AND ÐLAY ÂÉÏÓ ÅNHANCEMENTS ËIT", ÆÁØ YOUR NAME AND COMPANY INFORMATION TO ÉNTEL AT 1.503.696.1307, AND ÉNTEL WILL SEND YOU THE INFORMATION. ==== ÑÕÅÓÔÉÏÎ: ×HERE CAN É GET DRIVERS (ÁÓÐÉ AND OTHER) FOR THE ×Ä7000 ÆÁÓÓÔ2 HOST ADAPTER? ÁÎÓ×ÅÒ ÆROM: ÇARY ÆIELD (GARYF@WIIS.WANG.COM) ==== ×ESTERN ÄIGITAL STOPPED PRODUCING ×Ä7000 ÆÁÓÓÔ2 CARDS SOME TIME IN 1990. ÆUTURE ÄOMAIN BOUGHT THE RIGHTS TO PRODUCE THEM AND AS OF EARLY 1994 THEY STILL DO. ÃOLUMBIA ÄATA ÐRODUCTS ÉNC. OF ÁLTAMONTE ÓPRINGS, ÆLORIDA STILL PROVIDES DRIVER SUPPORT FOR THE CARD. ÔHEIR ÓÓÔ ÉÖ DRIVER PACKAGE PROVIDES SUPPORT FOR MANY TYPES OF ÓÃÓÉ DEVICES INCLUDING DISKS, TAPES, AND ÃÄÒÏÍ. ÁLSO INCLUDED IN THIS PACKAGE IS AN ÁÓÐÉ MANAGER DRIVER (EQUIVALENT TO THE ÁDAPTEC ÁÓÐÉ4ÄÏÓ.ÓÙÓ). É HAVE PERSONALLY TESTED THIS ÁÓÐÉ MANAGER AND IT WORKS WITH ÇÎÕ TAR W/ÁÓÐÉ AND THE ÃOREL ÃÄÒÏÍ DRIVER, SO MOST OTHER ÁÓÐÉ STUFF SHOULD WORK TOO. ÖERSIONS OF ÓÓÔÁÓÐÉ.ÓÙÓ PRIOR TO ÏCT 1993 DO ÎÏÔ WORK WITH THE ABOVE MENTIONED PROGRAMS SO BE SURE TO CHECK THE FILE DATE. ÔHERE ARE OTHER USEFUL PROGRAMS IN THE PACKAGE AS WELL. ÆOR INSTANCE É FIND THE ÔÁÐÅÕÔÉÌ PROGRAM VERY HANDY FOR DUPLICATING TAPES. ÔHE PRICE OF THIS PACKAGE IS $99 OR $85 AS AN UPGRADE OF A PREVIOUS VERSION. Á PRE-REQUISITE TO RUN THIS SOFTWARE IS THAT THE ADAPTER CARD MUST HAVE A ÂÉÏÓ ÒÏÍ VERSION OF 3.36 OR NEWER. É DON'T THINK CARDS MANUFACTURED BEFORE 1989 OR SO ARE COMPATIBLE. ÃOLUMBIA ÄATA ÐRODUCTS ÉNC. 1070  ÒAINER ÄR ÁLTAMONTE ÓPRINGS, ÆÌ 32714 (407) 869-6700 ==== ÑÕÅÓÔÉÏÎ: ×HAT IF É HAVE A ÓÃÓÉ DRIVE LARGER THAN A GIGABYTE (1024K) ? ÁÎÓ×ÅÒ ÆROM: ÇARY ÆIELD (GARYF@WIIS.WANG.COM) ==== ÔHE ÉÂÍ ÐÃ/ÁÔ ÂÉÏÓ ÉNT 13H DISK INTERFACE WAS SPECIFIED IN ABOUT 1986 WHEN A LARGE DISK DRIVE WAS ABOUT 60 ÍÂ. ÉÂÍ DECIDED THAT DISKS WOULDN'T HAVE MORE THAN 1024 CYLINDERS AND ONLY ALLOCATED 10 BITS FOR THE ÃÙÌ PARAMETER TO THE ÉÎÔ 13H INTERFACE. ÂY 1989, THIS WAS ALREADY A PROBLEM. ×HEN VENDORS BEGAN TO SUPPORT ÓÃÓÉ DRIVES UNDER ÉÎÔ 13H, THEY NEEDED TO COME UP WITH A TRANSLATION ALGORITHM BETWEEN THE ÃÙÌ, ÈÅÁÄ, ÓÅÃÔ PARAMETERS OF ÉÎÔ 13H AND THE LINEAR BLOCK NUMBERS USED BY ÓÃÓÉ DEVICES. ÖARIOUS VENDORS CHOSE TO MAP THE TWO SUCH THAT EACH ÉÎÔ 13H "CYLINDER" CONTAINED 1 ÍÂ. ÉN OTHER WORDS THEY EMULATED A DRIVE WITH 32 HEADS AND 64 SECTORS PER TRACK. ÁT THE TIME, LARGE DRIVES WERE AT ABOUT 300 ÍÂ, SO THIS WORKED ÏË. ÏNCE DRIVES LARGER THAN 1024 Í ARRIVED, A PROBLEM DEVELOPED. ÔHEY COULDN'T PROVIDE CYLINDER VALUES GREATER THAN 1023! ÃHANGING ALGORITHMS BECAME NECESSARY. ÔHIS IS PAINFUL SINCE ANY DISK FORMATTED WITH THE OLD ALGORITHM CAN'T BE READ USING THE NEW ALGORITHM. ÂY THE WAY, DIFFERENT VENDORS CHOSE DIFFERENT MAPPINGS, SO DRIVES FORMATTED WITH ONE ADAPTER CAN'T NECESSARILY BE MOVED TO A DIFFERENT ONE. ÁDAPTEC'S NEWER ADAPTERS (E.G. THE 154Xà AND THE 154XÃÆ) PROVIDE A ÂÉÏÓ CONTROL TO SELECT THE OLD ALGORITHM OR THE NEW ONE, AND THEY ALSO PROVIDE ÂÉÏÓ ÐÒÏÍS FOR THE 154X THAT WILL USE THE NEW ALGORITHM. ÔHERE IS AN ABSOLUTE LIMIT OF 16 Í SECTORS WHICH MEANS 8 Ç ASSUMING 512 BYTE SECTORS. ÔHE DAY WHEN THIS PRESENTS ANOTHER PROBLEM IS NOT TOO FAR AWAY (1995?) ÈOPEFULLY, WE'LL ALL BE RUNNING MORE SOPHISTICATED Ï/ÓES THAT BYPASS THIS LIMITATION BY THEN. ==== ÅND. ==== -- --/* ÇARY Á. ÆIELD - ×Á1ÇÒÃ, ×ANG ÌABS Í/Ó 019-72Â, 1 ÉNDUSTRIAL ÁVE ÌOWELL, ÍÁ 01851-5161, (508) 967-2514, EMAIL: GARYF@WONG.COM