Marciano, F

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f \ CERN - DD/DA/67/5 F. MarcL .... 'lO March 1967 IBM 1800 - CDC 6600 Data-Link Preliminary Specifications INDEX 1, Introduction 2. 01,1.tline of the system . 2,1 The CDC 6600 2,2 IBM 1800 2. 3 Data link 3. Operation 3,1 Status information from .1800 to . 3 '2 Status/control information from 3,3 1800 to 6600 data transfer 3.4 6600 to 1800 data transfer References Figures 67/402/3/mg 6600 6600 to 1800 2 1. INTRODUCTION This link is usc\l :i.n orL1er to t:t:ansfer to the 6600 blocks of checked raw data collected by the 1800 during each accelerator burst. Complete calculations are performed in the 6600 and results are sent back to the 1800 via; thE; l,inko 2. OVTLINE OF THE SYSTEM 2.1 The CDC 6600 The data link is connected ·t;o channel 11 (octal) of the 6600 via a data channel adapter for high speed data/status exchanges. There is also a connection to subchannel 6 of the multiplex3r for slow rate status input to the 6600. 2.2 The IBM 1800 The data link is connected to digital groups with'address 00 (data output) and with address 01 (status output)o It is also connected to digi ts.l group 64 (data input). and 'to three interrupt levels with decimal addresses'20,21,22 (future reassignment of interrupt levels is foreseen). Interrupts on levels 20 and 21 are entered as single bitso Interrupt on level 22 corresponds ·co process i.nterrupt status word ( of 4 bitso 2. 3 Data link The data link consiDts of two items z a) Data' link control unit (DLC) located in the proximity. ·of the 6600. b) Transmission equ:i.pment cmrni.sttng of cables, transmitters, receivers and special interface circuits. Eight cables 67/402/3/mg of tho type desc:r.ibed in OER\f report 65-·5y section 2,1, are employed and therefore a total of 80 signal lines is available. The cables are la:.Ld out in three sections, one from the 6600 area to the East compressor building~ another from the East compresi:::or building to the South Hall, the last one from the East compressor building ·i~o the East Hall (fig. 1). A junction box in the East compressor building is used ·in order to link the 6600 area to either the East Hall or· the South Hall area, depending on the location of the 1800" Part of the elect:r.0~1ics of the DLC unit is· common to the existing SDS 920 data link (CEHN report 65-40 and internal DD report DD/DA/66/10). The common parts are : 6600 control, data conversion register, or to DCA, MUX interface, power control. ~arts which are not in common are : - 920 control 7 O/P"flags? gates to 920, parity circuit,, 920 input flags ·- :fo:i::· one link. - 1800 control, O/P flags, gates to 1800, 1800 input flags -for the other link. 3. OPERATION 3~1 Status information 'from the.1800 to the 6600. Status. information is transferred to a register of the DL control (input flag register) when an XIO instruction is executed which specifies one word in memory having the :following charac-teristics : 7 Bit. 215 _always present .,. Bits 2°-25 "'\Tariable~ they express the value of the status transmitted,, The address of the digital output used is 01 and this code is either contained in the data word specified by the IOCO or in the second word of the· tab].e depending on whether di5'ect programme control or data channel control are usedo Bits 2°-2 ·are stored in the· input flag r..egister, which can be interrogated by the 6600 P.P. by means of,~ status request function followed by a 1 word input. Bi ts 2° -2 . of the latter word represent the same original 1800 'bi ts. The register is reset to.zero only when the 1800 executes a transfer with bit 215 equal to 1 and bits 2°-25 equal to zero. Bit 27 of the 6600 status input word .is set by the data link control,. when.ever the data link is operational which implies that. : a) Data link Il operational push button is on. b) Power is on. c) DLC to DOA connec:lions are made. Table of fig. 2shows a list of input flags with their conventional meaning. Noto.. : . Output digital group 01 Of' the 1800 is 'deVI.'ces connected to the 1800 (eog. Display)~ is connected, the above-mentioned output works ledge mode, which means that : used by other Wheri this device in request/acknow-a) Write mode control signal is kept at "O" level. b) Write request is contin.1wusly provided by the display system. c) Write acknowledge and write pulse are sent out with the status word. When the display is not connected the conditions are tho following a) Write mode control signal is kept at 11 1 11 lov~L b) Write pulse is sent out with ·the status word. In both cases the status output is initialized by the 1800 performing an Initialize Write Single Address (Area=OllOO, Funotion=lOl, Modifier=OlOOOOOO). 67/402/3/mg 4 3.2 Status/control information from 660Q to the 1800 A control/status word of 6 bits (2°-25) is transferred from a 6600 peripheral processor to a register of the DL control - 1· ,. (ou:t;put flag register) when a function instruction is execu-ted. The function word has the following characteristics. B.it 29 (synchroniser address) always present. Bit 26 (data link address) always present, Bi ts 2°-25 variable according to the control 02 the status which is transmitted. Table of fig. 3' shows a list of output flags with thej.r conventional meaning. OF2-4 1 OF2-5, 01!'2-6 are commands which prepare the data link e'i.?ctrdnics, they do not affect in any way the 1800. OF2-l and OF2-2 cause single 1800 interrupts respectively on level 10 (deCimal address 20) and on level 11 (decimal address 21). OF2-7 to OF2-10 have the following cha:tacteristics : • . 9 6 1 0 . . ·. 2 3 4 5 Bits 2, , 2., 2 , 2 are a),vmys ;Present. Bit.s 2 , 2 , 2 , 2 cm:i, b$ selected to give any of 16 possible status words, which will cause an 1800 interrupt on level 12 (decimal address 22). ·.As soon as this interrupt request is recognized its PISW word can be read into the A register of the 1800 and this makes possible to 'dotermine.which combination of the four bits has caused the. interrupt. Note : Only pulses or level· changes 'from 11 0 11 to 111 11 are .. recognized by the 1800 as interrupts, This carries two consequences :· a) 6600 programs should provide reset of the.output flags by executing a function with function word equal to ),100 whenever two subsequent identical flag combinations are set. This prec8.ution is not necessary for OF2-4, OF2-5 and OF2-6 which are only used by the data link control. b) "Link operational" being a static condition cannot be easily recognized by interrupt on level 120 Suggestion is made that the 1800 should .interrogate the 6600 by means of an'input flag to find out whether the link is operational. The 6600'will then set an output flag to specify this condition3 , 3. 3 Data transfer from the 18JO to the 6600 Blocks of 16 bit words are transferred from the 1800 via digital address 00. An XIO instruction is executed with an IOCC containing the tollowing information ~ Address of a data table - Area = 01100 - F'l:illction = 101 (initialize write) - Modifier = 01000000 corresponding to "write single address 11 mode. 67/402/3/mg 5 The table s]J;ould contain Word no. 1 - Scan control = 00 (single scan of table and stop with an interrupt) or scan control = 01 (no . interrupt and test if channel is busy). - Word count = n+l (n = number of 16 bit words in the table) Word no. 2 - Add:i;-ess of digital out'put e.g. 00 Following words - Block to be transferred. The transfer of words will be executed in a request/acknowledge . mode in the following way : a) Write mode·· control level is at 11 011 level b) Write acknowledge signal is set to "l" by the 1800 when write is initialized together with the "w:ri te 11 puls.$, wbile the first output word is sent out on the dat'a lihes. · · · · c) The data link answers not earlier than 8 µs from the time when the write pulse is sent out with a write request which causes t~e write acknowledge to be reset to zero, d) A second word is sent out with a write pulse while write acknowledge is set to one again. e) Every word of the block is transferred this way. The end of the block is recognized by an interrupt as specified by the scan control. Write pulses cause the accompa.nyi11g.J6 bit word to be stored in the conversion register of the data link control. From there two words are transferred to the 6600 PP, the +irst containa.ng the 4 most significant bits of the original 16·b{i; .. word, the second containing the 12 least significant bits'i ''· , · ,. The following sequence of instructions is necessary at the PP end Input select Activate channel Load number of words= m into A register (m~2 n) Input (IAM) Wait for disconnect Absence of write acknowledge signals from the 1800 for a period of about 100 µs will cause a disconnect to the 6600 and the latter will terminate the transfer indep.end~ntl.y from the amount of words transferred. 67/402/3/mg 6 Previous to the transfer the two computers should be brought into synchronisation by the following steps : 1800 SET INPUT FLAG IF2-2 = 1800 READY FOR INPUT INTERRUPT ON LEVEL 11 RECEIVED SET INPUT FLAG IF2-4 = 1800 WAITING FOR INPUT 6600 STATUS REQUEST SET OUTPUT FLAG 0:;;•2 ... 2 = INPUT REQUEST STATUS REQUEST WAIT I OUTPUT n WORDS~~~~~--~--~--~~~~~INPUT m WORDS 67/402/3/mg CM Loe CM Loe 7 -The following sketch shows the disassembling and assembling' of wor.ds from the 1800 to the 6600 central memory : DATA LINK CON-VERSION REGISTER PP Loe X PP Loe (X-1) 259 Y+l [ 211 259 y I BLANK 1800 BLANK 20 I ~: 215 r- J • • • ~ • 0 • • • • • . . . . . 20 ] IB.LANK I 215 20 215 20 20 BLANK I BLANK I~ 20'· ··. 215· 2 o· 215 212 67/402/3/mg 8 3 .4 Data transfer from 6600 ~;o 1800 The PP programme executes the following sequence of instructions Output select Activate the channel Load number of words to be transferred= m into A register Output (OAM) Disconnect The first two words are assembled into a 16 bit word in the conversion register of the data link control" The word is sent out onto the transmission lines together .. with a read request signal. At the 1800 end the Read Mode Control signal must be at 11 0 11 level in order to allow request/acknowledge operation. On receiving the first word with a read request the 1800 answers with a read acknowledge signal and with a read pulse. The read acknowledge signal travels to the data link control and causes a 33_~_()En<J. p_?-i~_ 9:f:p;p w~~.ds to be assembled and transmitted ~ith a new read request. If the interval of time between read acknowledge signals from the 1800 is longer than 100 µs a disconnect is generated which causes the 6600 to terminate the transfer i.ndependently of the number of words transferred. In order to input the block of words the 1800 executes an XIO instruction similarly to what has been described in paragraph 3.3 from transfer of 0 block in the opposite direction. The IOCC in this case contains ~Address of data-table ~ Area = 01011 ~ Function= 110 (initialize read) - Modifier ; 01000000 (read single address) The second word of the table contains 64 decimal which is the address of the digital input used for the·data link. The word m count should be equal to n + 1 with n = 2. Previous to the transfer the' two computers should be brought into synchronization by the following steps : 67/402/3/mg 1800 -SET INP~T,FLAG IF2-l = = lSOO READY FOR: OUTPUT .. , . · IN-TERRUPT ON; LEVEL 10 . . . ., :· ... ::'., RECEIVED SET INPUT FLAG IF2-3 = = 1800 WAITING FOR OUTPUT XIO .AND WAIT - 9 ... : ;: ... • / • l ~ STATUS RE.QUEST ; t <~{:)ET ~ O~PUT FLAG OF2-l = OUTPUT fl:EQUEST .. STATUS REQUEST WJJ.T INPUT n WORDS ------~_,,--------=--~.· ~"DCr.r m WORDS 67/402/3/mg 10 ... -Ref erenc,e·s 1. Control Data 6600 Series Computer Systems. Refleren-ce Maµual 9' 2. IBM 1800 Data Acquisition and Control Sy~tem Functional Characteris-tics. 3. IBM Special Feature Report No. 2-0016. High Speed Digital Input and Output. 4. F. Marciano and H.J. Slettenhaar - A data'link from PS experimental area to Mercury computer CERN report 65-5. 5. F. Marciano - A data link between two computers CEBN 65-40. 6. s. Bunodiere, J. Austin - Manuel du Data Link CERN DD/DA/66/16. 67/402/3/mg "' ~ s ~ 1-zj ...... (Jq ~ + / /' , I \ I i .. --I__ .. __ ,.:f ! ~- - -+ ········· .. ,, ~ -_,,__,:,--.?.:-~--.9;;1'; + ~--y / ,;' // ,j t ,, ,, ,; /1 •' • ,, ,,. l' ,, + + / '~1 ·,_, \ /'~/, \ I // \ ( --~v:> \ . ~ ---- "~. ------1 ·~-...... 'i ' -\--- t -.... ~.,..,. \ _ -----==-\-_ I -----cc_ ! --. ,t '11 ---::----- ' \ _-:,----;~· \/ii~~: I \ _ _,_ .ji\ .' 1_,' I ' '/" '~ I ' ,,;\ ( \ ',_ I:: / ~ \ ',,:;_, , I ~ \ ~ .\ ~ I " I tt I ~ ., I' I I " I+ _J_ ~ I :t !t t '+ It '• LEGENDE·. ORIGINAL MERCURY DATA LINK ADDEO CABLES DISTANCES. CDC 6600 -JUNCTION BOX ,. 364 m JUNCTION BOX -TERMINAL BOX EH " 287 1n JUNCTION BO:< -TERMINAL BOX SH ,. 532 m JUNCTION BOX -TERMINAL BOX HCR ,._ 46.4 m CDC 6600 -TERMINAL BOX EH " 651 m CDC 6600 - TERMINAL BO:< SH = 896m -, i i j I i I .1-f. JNPUT FLAGS °' -..;] '-..._ -!='-0 rET BY I\) NAME MEANING 1800 O/P TESTED BY I DCA · 1 DCA STATUS I JYIUX '-..._ STATUS WORD BITf MUX, DC:Ac ···. ·· BITS . RESPONSE \>I BITS 'S' 0\4 I IF2-l 1800 READY I 20 I MUX DCA. I 20 I 1 I 2 FOR O/P IF2-2 I 1800 READY I :21 I JYIUX DCA FOR I/P ' l· 2··'·· I 2 I 3 IF2-3 I 1800 WAITING I l I DCA I 22 I 4 FOR O/P I -;,: I I 23 IF2'.'""4 I 1800 WAITING 2-' DCA I lOB FOR l/P :[F2-5} I w4 , I JYIUX DCA I 24 i' 20B I 5 AJ,ry STATUS 5 DCA 25 40B IF2-6 SET BY IF2-8 I LINK OPERATIONAL) DLC J JYIUX DCA I 27 t 200B I 6 ·~,, Fig. 2 67/402/3/mg 0\ -.J "-.. -1'>-0 f\) "-.. \.J.l 'S' (JQ OUTPUT FLAGS NAME 1 !SET BY I I INTERRUPT LEVEL MEANING FUNCTION CODE CAUSES STATUS WORD BITS OF2-l I 6600 REQUESTS O/P I DCA I 1101 B I INTERRUPT LEVEL 9 OF2-2 I 5600 REQUESTS l/P I DCA I 1102 B I INTERRUPT LEVEL 10 OF2-3 I STATUS AVAILABLE DC.A _ _ ·--~1X3 B ( *) INTERRUPT LEVEL 11 QF2-4 O/P SELECT DC.A 1104 B DA'PA L]NK SELECT10Nl OF2-5 I/P SELECT DCA 1110 B DAT.A LINK SELECTJlOJI-OF2-6 STATUS REQUES DCA 1114 B DllTA LlNK SELECTXO OF2-7 DCA 1107 B INTERRWPT LEVEL 11 20 OF2-S ANY STATUS DCA lll3 B INTERRUPT LEVEL 11 21 - r; OF2-9 DC.A 1123 B INTERRVPT LEVEL 11 22 .... ~ INTERRUPT LEVEL 11 23 OF2-10 DC.A 1143 B ' (*-··y BITS 2°, 21 , 26, 29 always present, BITS 2 2, 23, 24, 25 represent a variable code -!= O 67/402/3/mg INTERRUPT 9 10 11 ±¥_~~filw;p~·· I DECIMAL LE\TEiL. : -~ ADDRESS ' . ~' .. «~ -.· ... :·~-10 20 11 21--12 22 Fig. 3 HEXADECIMAL ADDRESS 14 15 16 

IBM 1800 - CDC 6600 data-link preliminary specifications

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