226 NAVY UICERWAItP SOIRC LA Mn LOImON COMa ~~~ 9/2 wiften BOOTSTRAP II UNIVAC 1230 GFNFRAL. PURPOSE 1)1817*1. COMPu TER ttrtu) MAR 7D S BOTSEAS.

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1 226 NAVY UICERWAItP SOIRC LA Mn LOImON COMa 9/2 wiften BOOTSTRAP II UNIVAC 1230 GFNFRAL. PURPOSE 1)1817*1. COMPu TER ttrtu) MAR 7D S BOTSEAS. 0 POTTER. C BICKER UNCLASSIFIED MIL TM UII fl70 PA.

2 I I P P 7jy COPY To NIJSJ I robleni No. f l EJ Y O A oa io8oooo I 9 J OO_(%) NAVY IJTTh1 ;RW/tTl:I r O(JND JABOHAT0J Y 7, N 1W.0NDON, CONNECTICUT ( _.,klihe1) DOOT TRAP H UN I VAC 1230 Q]:N1 HAL j iinposi : )IGITA L JX 4PUTER, RIAL 6;./, tv t/ H I ( T7 George/Botseas, Davi d/potter C1air/Beck. NUSL Technical Memorandum No / / /(/3 Mar INTRODUCTION The Univac 1230 General Purpose Digital Computer, Serial 62, > contains a special purpose auxiliary memory comprised of sizty four 30bit words. This memory area, commonl y referre d to as Wired Bootstrap Memory, is divided into two groups of thirtyt wo word s each. Each group of words has been wired to contain a special purpose LOAD program which may be used to enter other programs such as C( 4PBOOT, UPAC and SLUPAK into the computer. These LOAD programs, which operate in a nondestructive readout mode, and are selectable by operation of the ]300TSTBAP PROGRAI4 switch, are known as Wired Bootstrap s I and II. U C Wired Bootstrap I, better known as the Paper Tape Bootstrap, is described in NU L Technical Memorandum No This memorandum is devoted to Wired Bootstrap II. WIRED B0OTSTP P II / General Wired Bootstra p Ii, commonly referred to as the 1a netic Tape js Bootstrap, in the UNIVAC 1230 General Purpose Digital Compute r, / Serial 62, was designed specifically to input a program which has h been written on magnetic tape in Bootstrap II Format. Input is /i P / via the Magnetic Tape Unit tied to Computer I/O Channel 7. /! i 11 T :1 V /J 2!L IJ

3 I NUSL Tech Memo No. 22U _ 61i_70 Bootstrap II Format The core image of a record written on magnetic tape in Bootstrap II Format is illustrated in Figure I. This record must be written in Modulus 5, Octal Format, Odd parity at 556 BPI. Figure II illustrates one 30bit word recorded on magnetic tape In Modulus 5, Octal Format. Flowchart of Wired Bootstrapj A simplified flowchart of Wired Bootstrap II is shown in Figure III. Machine Coded Program of Wired Bootstrap II An annotated copy of the machine coded program is presented in Figure IV. Note that Wired Bootstrap II, like Bootstrap I, occupies memory cells through DependIng upon the position of the BOOTSTEAP PROGIW4 switch, either Wired Bootstrap I or II will be transferred to these core locations. Operating Instructions To load a program using Wired Bootstrap II, perform the following steps: 1 Mount the program tape on MTU Set the BOOTSTEAP PROGRAM Switch to II. 3. Depress OP STEP. 4. Depress MASTER CLEAR. 5. Depress LOAD. 6. Depress START. Upon completion of Step 6, the program will be read into core and executed. If an error Is detected during the READ operation, the Bootstrap program will rewind the magnetic tape and another BEAD will be attempted. T $d _Ii 2 L;

4 SUMMARY OF WIRED BOOTSTEAP II OPERATIONS After the Bootstrap II Program has been initiated: NUSL Tech Memo No a. The computer performs initialization and assumes control of the 1540 Magnetic Tape Unit. b. An input buffer is established resulting in the pseudo buffer control word being automatically transferred to the Input Buffer Control Register An external function command, interpreted as REWIND/READ, MOD 5, OCTAL, ODD PARITY, 556 BPI, Is issued to the Magnetic Tape Unit. d. Upon receipt of this command, the MagnetIc Tape Unit rewinds and commences to read the tape mounted on logical unit 1. e. Since the lower half of the Input Buffer Contra). Register contains the address 00105, the first word (WORD 0 in Figure I) transferred from the Magnetic Tape Unit Is stored in memory cell PrIor to this and each subsequent transfer, the lower half of the Input Buffer Control Register is automatically incremented by.l. f. The next two words (WORDs 1 and 2) received by the computer are stored in memory cells and respectively. g. Since WORD 2 verstored the contents of the Input Buffer Control Register 00107, WORDS 3 through N of the inputted record will be stored within the memory area defined by the address limits found in WORD 2. h. Upon completion of the READ operation, an exterral interrupt and a status word are transmitted to the computer. i. If the status word Indicates a good read, a checksum check is performed to ensure that the load is good. If either the magnetic tape status word or the checksum check reveals an error, the program will jump to address and another read 18 attempted. 3

5 NUSL Tech Memo No j. If no errors are detected, it Is assumed that the load was good and control is transferred to the entrance address of the inputted program. L J P IJL t L GEORGE 0TSEAS DAVID POTTER CLA BECERR Computer Specialist Mathematician Mathematician 4 I ;,.

6 NIJSL Tech Memo ) ORb 0 1. ( 1R q JCC bdress FXR ADDeGS3I o o& * oc p o Aø 2 t D ESS DD fziss cc P.o R.A O P 0G M 3 4 Pp,ocRMM /t rr. WORD 4, 1.. ALL AbDSES,ES ARE 35OLL)TC )or.b d. C.O JT I,J S r C su i r o J o )OR D 0 P1J uj OR 3. op,d : F R T.JO Of ( oc RAw piI J5T 8t ECO ot3 rt pe, 4i jd s1. 8C,jg zr1, r J I. i OD5) ra L FO Ar ODD p rt /, A.r (. 1f. u1stp. I C &D c QRmI T.

7 NIJ ;I. Tech Metrto oxtoc SIDE P 02. oi TH FR.AmE rk s DGC P o 4 )3 o o f o3 JE $T I Q P o O 07 A 3S PORT i P I, to 0, II o oq 7TH P r+ t 12 i + r2. I: OR AR. D ) EC.T QfJ P I? I I? U. is fl P 20 I 15 Zo l 4,.rH P v P 2( * PAR.IT I B 2 t 2? 2, % 27 t cg.aw c ( I mp C t 2R I 00 1j 1 JJ j,30 rr. o v o r _ )LU5 C L f t O A1

8 NUSL Tech Memo J. i0 e) ( 1 [I T R T A. I ] ( 00D LOP) { t I r c vni ArE ( ) ( [ L ER J S J E L H I I rj )PL)T u F u4 i,4 p 1, ror.e Rfl $ Ik3TVRRUP1 I R.icTE R.c Zo3 STOR C P 10 5 )2. I J XT., i E R* )PT R Gt.T I ) L L c ) S,tv PLIF,ED *tagr A#v oc t..3tq.(b Oo STRAP. 4..

9 T USL Tech Memo ADDRESS INSTRUCTION NOTES Lock out all ext. interrupts/ CC( 4 for Demand Cont Terminate all buffers/excc 4 for Request Control Master Clear Mag Tape Units oooo Store RILS in external interrupt registers \ Store jump Instruction in external interrupt J register Return address + B Release interrupt lockout Request Control of Mag Tape Unit Unlock external interrupts on Channel l Delay.Jump to If external interrupt ) Is rec d Establish input buffer RewInd/Read first record Return address * Bl Wait for Interrupt. Jump to when rec d Test checksum Good load? If not, jump to Yea. Jump to program entry cell Mag tape status code OK? No. Try again Yes. Release interrupt lockout and jump to addre ln Bl External interrupt jump instruction EXCa4 for Rewind/Read/ 40D 5/OCTAL/ODD/556MT1J 1 FIGURE IV Machine Code Listing of Wired Bootstrap II