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Summary of Contents for 5091-P8e

Page 1: ...5091 P8e MAGNETIC TAPE SYSTEM TECHNICAL DESCRIPTION PUBLICATION NO SM 06 ...

Page 2: ...DATUM INC 1363 s State College Blvd Anaheim California 92806 5091 P8e MAGNETIC TAPE SYSTEM TECHNICAL DESCRIPTION PUBLICATION NO SM 06 ...

Page 3: ...SERIES 5091 MAGNETIC TAPE INPUTI OUTPUT SYSTEMS FOR MINI COMPUTERS ...

Page 4: ...TERMINATION CARD By providing a single termination card this option allows interchangeability of the tape units at will in a multiple tape unit system SPECIFICATIONS Weight Power Number of Tracks Data Density Rewind Speed Reel Size Operating Temperature Mounting Single tape system less than 100 Ibs 117V 60 Hz single phase regular outlet power 300 watts per tape unit 7 or 9 IBM compatible 9 track 8...

Page 5: ...Mount 1 Pertec a Speeds of 12 5 ips to 75 ips b Ree 1 sizes 7 to 10 1 2 c Read after write is standard single gap optional 2 Wangco a Speeds of 12 5 ips to 75 ips b Vacuum column available on 10 1 2 reel models at 25 37 5 45 or 75 ips c Read after write is standard single gap optional e Write or read on the fly continuous tape motion f Edit mode if transport is so equipped 1 ...

Page 6: ...FEATURES continued g Memory extension h Mixed 7 or 9 track i Up to four drives j Three cycle data break 2 ...

Page 7: ... is provided Either single or dual gap machines can be accommodated Tape transport mot ion control Cyc ic Redundancy Check Character CRCC and l ongitudinit 1 Redundancy Check Character LRCC generation and checking inter record gap generation and status reporting are included All Write clocks and delay times are derived from a crystal control Jed oscillato No lIone shots or RC delays are utilized T...

Page 8: ...pe speed 1 2 PHYSICAL DESCRIPTION The DATUM Model 5091 NRZI Contro ler complete on three large circuit boards is designed to be installed in the PDp8e computer mainframe Figure 1 1 shows this installation l 3 SPi CIF ICAT IONS Inter record gap 7 tra k Inter record gap 9 track Ci rcu i ts Operat ng Temperature Storage Temperature AI t i tude Relative Humidity Interface Voltages DTL 900 series or TT...

Page 9: ...THREE BOARDS REQUIRES FOUR SLOTS TAPE MACHINE 1 CABLES TERMINATE HERE TAPE MACHINE 2 o o INTERCONNECT ASSEMBLY 76258 Figl re 1 1 I nsta11ation of Model 5091 NRZI Controller 1 2a ...

Page 10: ... nter preted as Cl h gh signa 1 Figure 1 3 illustrates the configuration for which the interface has been designed 1 4 MAGNET I C TAPE FORI1ATS Figures 1 4 and 1 5 i11ustrate the IBM and USASCI I magnetic tape formats for 7 track nd 9 track tapes respectively 1 3 ...

Page 11: ...NATION I I I 5V I I CABLE DRIVER I CABLE RECEIVER I I I 220n I J I ___ r I I I I L ________ L ____________ J DTL 84l or TTL 7416 7J 37 DTL 8XX Series TTL 71 lXX Series 7438 7 40 or equivalent or equivalent Interface Circuits ...

Page 12: ... EVEN PARiTY FOR BCD TAPES 4 EACH BiT OF THE LRCC IS SUCf l THAi THE TOTAL NUM8ER OF Ill BITS IN THAT TRACK I JClUDiNG THE LRCC IS EVEN IT IS POSSiBLE IN THE 7 TRACK FORt 1AT FOR THIS CHARACTER TO BE ALL ZEROES IN WHtCH CA E A READ DATA STROBE WILL NOT 8E 5 A FILE t ARK IS A S NGLE CHP F ACTER RECCRD HA flNG 111 BITS IN CHANNelS 4 5 6 AND 7 FOR BOTH THE DATA CHAR l CTEF I ND TH LRCC THE FI LE 1 A ...

Page 13: ...AINS O D DATA PARITY 4 E L CH 3 T OF THE LRCC IS SUCH TnAT THE TOTAL NUriSER 0 l SiTS IN THAT TRACK INCLUJING THE CRCC AND THE LRCC IS EVE IN THE9 TRACK FORMAT THE LRCC WILL n VER BE A ALL ZEROES C 1P RACTEK 5 IT 1S POSSIBLE FOR THiS CRCC CHARACTER TO E ALL ZEROES IN WHICH CASE A READ DATA STROBE WILL NOT 8E GE ERATED 6 A FILE l l F K IS A SINGLE CHARACTER RECORD HAVING 1 BITS IN CHANNELS 3 6 AND ...

Page 14: ...e should have at least one twist per inch and a minimum insulation thickness of 01 inch The ground wire of each twisted pair should be terminated to grqund as close to the origin or destination of the signal as possible within 6 inches maximum to minimize ground loop current crosstalk effects 2 2 FORMATTER TRANSPORT s INTERFACE 2 2 1 Formatter to Transport Transport Address SELECT A through SELECT...

Page 15: ...OFC Offl ine Command A negat ive going pul se which causes the selected transport to revert to manual control Transport must be manually placed liON LINEII before it can again be operated The offline command can be transmitted to a tape transport that is rewinding even though the transport status indicates NOT READY SWS Set Write Status The level of this signal is inspected within 20 microseconds ...

Page 16: ...t ramp down In NRZI transports this signal also generates the LRC char acte r DDS Select High Density Low select high density for NRZI For matter only for 7 track transport 2 2 1 3 Write Data WDS Write Data Strobe This is a clock used to copy the write data WDP and WDO through WD7 into the selected transport write flip flops The data levels must be static during WDS and the trailing e e positive g...

Page 17: ...port is rewinding The level remains low until the transport completes the automatic return to load point sequence but the transport does not become Ready until approximately 5 second after the R JO signal terminates FPT File Protect A level that is low when the selected trans port has a supply reel of tape mountep that does not have a write enable ring ins tall ed lOP Load Point A level that is lo...

Page 18: ...High 7 track 001 Data Density Indicator Low High Density Selected High Low Density Selected Read Data Read Clock RDP ROO through RD7 Read Data Read Data Clock The read data is completely IIbufferedll in a special register The da ta is allowed to change until just before the leading edge of the read strobe pulse RSTROBE and is static throughout RSTROBE and until a minimum of 1 s af ter RSTROBE 2 5 ...

Page 19: ... Controller performs three basic functions These are 1 Control 2 Write 3 Read The Controller provides control over the selected tape unit includ ing all timing necessary to perform automatically all Write Read Rewind Space Forward or Backward and Rewind commands Upon completion of the commanded operatio status is provided so that the co puter can ascertain whether the operation was performed corre...

Page 20: ...REA STROSE A LI ______ 1 ___________ T EA ArA eb _ R PARITY 000 PARITY 1 _CPAC_NR_ _O __ I 1 TR 6 I p ql TY f f EN ODt r CHECK STATES CR3 WRITE DATA SELECT CATES PoAlT WRITE STORAGE SH MTA RUilSTER ___ r _ J _ CO I Ii2 FL G i C RE ISTjJC 7 Tit C l r SET DATA FLAG CATA TAANSFE OATA FLAG t STATES 1 fR ACK CONTR01l26 27 fi I i W ACKNC ll O E OdAY STATUS AlT I d JoI A T COU HE R S I SPEED CLOC K ____ ...

Page 21: ...ed on each tape unit 3 2 BLOCK DIAGRAM A simplified block diagram of the NRZI Formatting logic is shown by Figure 3 1 The block diagram illustrates the various functions performed by the standard 7 track 9 track NRZI Controller and shows the relationship be tween the control the tape transport units and the computer adapter section 3 2 1 Command Register Valid Reject Logic When a command is output...

Page 22: ...red the Data Busy status must be utilized by the computer to initiate the next command as soon as Data Busy terminates 3 2 3 Transport Control The transport control logic develops the forward reverse rewind and offline commands to the selected tape transport unit under control of the command register and the state counter 3 2 6 State Counter and Main Control The State Counter breaks the major oper...

Page 23: ...it or normal mode 4 Reverse or Forward motion 5 Seven or nine track tape unit selected The pre and post delays are used to erase the inter record gaps IRG and to halt the head in the correct position in the IRG when reading State 0 the rest state is the state the Controller enters after completing an operation State 1 Predelay is used to wai t for the tape unit to get up to speed nd to erase part ...

Page 24: ...e between the command to stop and the actual stop time This delays termination of the CBUSY signal until the tape unit has completely halted in the IRG The OBUSY stntus terminates when State 5 is entered Thus suc cessive Writes or successive Reads may be executed on the fly without stopping in the IRGls State 6 r verse motion halt time out is similar to State 5 except for rev erse mot ion commands...

Page 25: ...s Odd parity is automatically selected for 9 track tape uni ts The output odd pari ty is used by the Parity Generator and Check logic 3 2 9 Parity Error Detect The Parity Error Detect logic searches for one or more parity errors in each tape record Any detected errors cause the Parity Error Status bit to be set The Read Control logic uses the Read Clock Activity Sense logic RCAS output to enable t...

Page 26: ...edge of the next Read strobe occurs This deletes the requirement for a storage register in the computer adapter section This register would otherwise be required to retain the data for the maximum possible time after the Data Flag is set to give the computer the maximum amount of time to accomplish the data transfer The outputs of the Read Data Storage Register are routed to the rest of the logic ...

Page 27: ... and or contained an odd number of tape characters 3 2 14 File Mark Detoct The File Mark Detect logic checks for 7 track or 9 track file marks depending upon which type of tape is selected The EOF status bit is developed if a file mark is detected in a forward or backward direction 3 2 1 5 Rc d Control Logic The Read Control logic controls data transfer during State 3 until the IRG is detected at ...

Page 28: ...eed a register to store computer output data The Data Transfer logic operates on a request response basis via the Data Flag and Write Read Acknowledge 1 R ACK si gnal s Each dcJta character is requested a full write clock period before it is needed The computer can respond any time within this period with a W R ACK strobe pulse to load the Write Data into the Write Storage Register 3 2 17 Parity G...

Page 29: ...enerator calculates the CRC Character while writing each record as each data character while writing each record as each data character appears on the write data bus At the end of the record 9 track only the 1r i te Control logic gates the CRce onto the bus and generates a Wr i te clock pu 1se to wri te the CRe Character The LRC Characte r is then written to finish the record The CReC may be a 11 ...

Page 30: ...tape speed select 16gic The Write Control logic also sends the Write Most Significant Byte WRMSB signal to the Computer Adapter This enables the odd even characters to be separated when unpacking a computer word into two sequential tape characters 3 2 22 fLystal Osci 1lalors and Tape Speed Select The Crystal Oscillators provide stable precision clock frequencies for packing densities of 800 556 20...

Page 31: ...dapter returns the W R ACK signal which clears the Data Flag and is used to strobe the Write data into the Write Storage Regis ter for rite operations When the Computer Adapter dcsi cs to hnlt data transfer it generatcs the HALT signal and the Data Flag signal is disabled 3 2 25 Delay Counter The Delay Counter is a flip flop divider chain that counts the Speed Clock pulses to provide precise time ...

Page 32: ...e is reached at which time State 3 is terminated 3 3 COMMANDS 3 3 1 Basic Commands Basic Commands provided by the Formatter are 1 Read one record 2 Wri te one record 3 Space 4 Wri to File Mark 5 Erase 3 inch gap 6 Rewind 7 Offline 8 Clear 3 3 1 1 Read and Space The Space operations can be a single or mUltiple record under control of the STOP SPACE Computer Adapter signal In addition the backspace ...

Page 33: ...ler goes Busy u ntil the re ind is terminated to p ovide a means of interrupting the computer upon termination of the operation The Offline command never sets the Formatter to the Busy state and maybe sent to a selected tape unit even if the tape unit is Not RCud1 II because it is performing a rewind operation 3 3 2 Command and Mode Combinations The list of possible commands executable by the Form...

Page 34: ... X i 1 1 11 i j I Wr i te 1 R ecord ed it X 1 1 X I r i r t I I i 3 I I 4 Space Forward 1 Record _t t I I 5 I 6 i 7 Spece Reverse 1 Record I X I I I 8 S ce R R ords I X I 4 5 I I 11 Erase 3 I nch Gap i I f 12 Erase 3 h _n y rite i r__k_ l_ __ _ _ r _X t___ J __L II i I I I I i t_ _ _ _ _ _ _ _ t__ h_e_n_ _ __ L_ e_ _ _p e__ _r _i _____ I 1 f 1 xi X lit l i l j I I I I _1_5_ _I_n_it_i__ a_te_Re_w_i...

Page 35: ...block diagram by the actual octal lOT instruction cod The fol lowing gives the basic uses of the IOT s by octal code OCTAL COO E 6701 INSTRUCTION Skip on Error Flag or MTF set _ _ _ _ _ _ _ _ _ 6702 Clear il C _ _ _ _ _ 6706 St at us AC 6i11 Skip on Controller Ready __ _ _ _ 2 1 __ 1 _ _ _ _ _ _ r_ _l __ _ 6714 Inc 1us i ve OR AC Cont ro1 Reg is te r _ _ _ _ _ _ _ 6716 AC Control Register and Clea...

Page 36: ...es the contents of the status register through the input gates to the AC register Since the AC register is cleared automatically by lOT 6706 there is no need for the program to clear the AC register first Interrupt Skip Control register bit 9 enables the interrupt logic so that the computer is interrupted if either the EF or MTF flag is set The program may test for the tape controller Interrupt by...

Page 37: ...ate an interrupt if bit 9 is set in the control register If the command is not a valid one the Reject status bit is set and the Error Flag is set Actual data transfer into or out of core memory is controlled by th data transfer logic The data transfer logic operates the data break mode 3 9 7 The data transfer logic interfaces with the tape transport controller via the Data flag and the HALT and Wr...

Page 38: ...inputting to the computer MB register For normal 9 track operations the eight bit tape characters plus the parity bit are gated to the nine least significant bits of the computer MB register bus When a break request has been initiated by a device the device at time state 4 must verify that it is the highest priority break request device for that particular cycle This is done by enabling the accumu...

Page 39: ...to put data into the core during a Read mode or take it out of core for a Write operation During the word count and current address portions of the break cy cles the data that is brought out of the word count and current address lo cations is incremented before being restored into memory by a signal called INCR This incrementing is done at the beginning of the cycle to increment the location befor...

Page 40: ...g EF or Mag Tape Flag MTF MTSF Octal 6701 The state of the EF and MTF status bits is sampled If either or both is set a pulse is returned on the skip bus to skip the next sequential instruction This instruction allows the program when interrupted to test the tape controller to ascertain if the tape controller is generating the in terrupto The EF and MTR generated interrupt is not cleared until eit...

Page 41: ... select bits ACO AC1 and ACZ into the control register and linclusive ORls the rest of the AC into the control register Load Control Register HTCL Octal 6716 The load control register instructton produces different results depending upon the status of the tap transport controller i e busy or not busy a Controller Not Busy The EF and MTF flags are cleared The contents of the AC register are loaded ...

Page 42: ...es mode control over the EDIT function the marginal read threshold for single gap read checking of each record after it is written THR1 and the low data recovery read threshold THR2 The OFFLINE command bit is also located in the control extension regi stc r Control Register Extension Format _____________ AC 6 7 8 OFFLINE I Mode 9 10 11 Memory Extend odel r emory Extend l 9 10 11 0 0 Normal 0 1 Edi...

Page 43: ... execute the command pre sent in bits 6 7 and 8 of the control register if a legal command It also causes bit 5 Erase 3 Gap of the control register to be reset to zero if on MTGO can be jumper selected to load the control extension register from the AC register instead of lOT 6717 This gives control over the OFF 1i ne conimand edi t mode RTHRl and RTHR2 modes and memory extens ion wi th MTGO 3 9 1...

Page 44: ...ng of Tape I Illegal Command Parity Error EOF End of Fi Ie 11 EOT End of Tape Odd Number of Characters _____ _____ 1 Record Length Incorrect WC 0 long we I 0 short __________ A Oat Transfer Timing Error 9 Tr ck Tape Unit Selected MT Mag Tape Flag __ ___ 3 45 ...

Page 45: ...3 9 12 Rewinding AC 1 Set while selected tape transport unit is in rewind mode 3 9 13 Set while selected tape transport unft is on the beginning of tape BOJ rna rke r 3 9 14 111 ega 1 Command AC 3 l11egal commands are a MTGO command is issued when tape controller is busy b MTGO command is issued to a tape transport unit that is not ready even though tape controller may be ready c Wri te One Record...

Page 46: ... of File AC 5 The EOF status bit is set if an end of file mark is encountered during any tape movement operation except Rewind The EOF status bit is also set if an end of file mark is encountered on a Space Forward or a Space Reverse When the space commands are termina ted due to a file mark the program can interrogate WC to determine the num ber of records spaced over prior to encountering the en...

Page 47: ...this status bit is set whenever the WC overflow does not agree with the number of words actually read The EF is set when MTF is set upcn completion of the Read operation and the Interrupt is generated if enabled 3 9 20 Data Transfer Timing Error AC 9 This status bit sets whenever a word is not transferred in time in either a Write or a Read cycle The EF status bit is set when the MTF is set at the...

Page 48: ...egister and Flags Control Word Format The control register bits are illustrated in conjunction with the bits of the computer AC register ACO AC1AC2 AC3 AC4 ACS AC6 _J_ c_ E 1o 1 11 I NOT USED UN IT COMMAND RESET i Il I SELECT 7 TRI CK PARITY O EVEN 1 000 CORE DUMP MOOE ERASE 31t GAP Tape Unit Select Code AC AC 2 0 0 0 I I 0 1 1 Tape Unit 7 TRACK DENSITY O LOW l HI GH ENABLE EF OR MTF TO INTERRUPT ...

Page 49: ...e command regi ster The control register is loaded or modified by the computer program using either MTLC or MTCM lOT instructions See Section 3 9 11 for commands explanation 3 9 23 1 Erase 3 Gap ACS This causes three inches of tape to be erased This bit may be used by itself or in conjunction with a Write or Write EOF to erase a bad section of tape A gap will be erased on the tape if MTGO is execu...

Page 50: ...are set MTSE lOT is used to determine whether HTF or EF caused the interrupt 3 9 23 4 7 Track Parity AC3 When the NRZI Formatter is in the Remote mode this bit controls the Write Read parity selection for 7 track tape units 0 even parity 1 odd parity 3 9 23 5 7 Track Density AC 10 When the NRZI Formatter is in the REMOTE mode this bit controls the selection of Write Read density 0 low density I hi...

Page 51: ...ind to the beginning of tape The program may initiate rewind on one unit and then inmecJiately select a different unit and continue operating while the origi nuf unit is re oJinding a If the program does not execute either an MTLC 6716 or an MTCM 6714 to select a different tape transport unit priol to the termination of the rewind to the r iginal unit the MTF will be set on the completion of Rewin...

Page 52: ...t to the initial buffer u ddrcss minus one the c register must be set to the twos complement of the number of twelve bit computer words to be used If WC is set to less than the actual record length the indicated number of words is read in and data transfer halts although the tape con tinues moving until it reaches the next inter record gap If WC is set to greater than the actual record length the ...

Page 53: ...the inter record gap IRG is erased The tape transport unit halts and the MTF is set t9 interrupt the program if enabled The Read After Write logic performs both vertical character and longitudinal parity checks on the written record For 7 track operations the CRe character is deleted and the LRC character is generated after three blank characters If a single gap tape unit is used the program shou1...

Page 54: ...ace over The computer eA core location need not be set up since it is ignored When WV overflows or when EOF or EOT is detected the tape trans port unit is halted in the IRG and MTF is set to Interrupt the program if enabled Records are spaced over continuously ithout stopping in the inter record gaps Parity is checked and the EOF status hit is set if an EOF terminates the Space Forward operation A...

Page 55: ...ates the space reverse operation A file mark is counted as a record 3 9 24 7 Test Read This function is identical to a Read One Record command with the exception that the tape controller will also input the LRC and CRe NRZI only characters to the computer in the fon are mode The WC register should be set to the t O s cqmp1ement of the number of tape characters two 9 track or 7 track The command is...

Page 56: ...DATUM INC 1363 S STATE COLLEGE BLVD ANAHEIM CA 92806 714 533 6333 TWX 910 592 1289 ...

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