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- ╚ERE ARE THE ANSWERS TO ├OMMODORE ╘RIVIA ┼DITION #8 FOR ╩ULY, 1994
-
- ╤ $070) ╧N A ╨┼╘ SERIES COMPUTER, WHAT VISUAL POWER-ON INDICATION WILL TELL
- THE USER WHETHER THE COMPUTER HAS ╥EVISION 2 OR ╥EVISION 3 ╥╧═S?
-
- ┴ $070) ╥EVISION ╠EVEL 2 ╥╧═╙ (THE ONES WITH MORE BUGS) POWER UP WITH:
- *** ├╧══╧─╧╥┼ ┬┴╙╔├ ***, WITH '*' IN PLACE OF THE MORE FAMILIAR
- '#' CHARACTER.
-
- ╤ $071) ╘HE ╔┼┼┼-488 INTERFACE IS SOMETIMES CALLED THE ╟╨╔┬ INTERFACE.
- ╫HAT DOES ╟╨╔┬ STAND FOR?
-
- ┴ $071) ╟ENERAL ╨URPOSE ╔NTERFACE ┬US. ┴NOTHER NAME IS ╚EWLETT ╨ACKARD
- ╔NTERFACE ┬US (╚╨╔┬), SINCE ╚╨ DEVELOPED THIS STANDARD FOR ITS
- ISTRUMENTATION DEVICE NETWORKING.
-
- ╤ $072) ├OMMODORE MANUFACTURED AT LEAST TWO HARD DRIVES WITH ╔┼┼┼-488
- INTERFACES. ├AN YOU NAME THEM?
-
-
-
- ┴ $072) ╘HE ├OMMODORE ─9060 AND ─9090. ╞ROM THE CBMMODEL.TXT FILE:
- * ├┬═ ─9060 5 ═┬ ╚ARD ─RIVE, ─╧╙3.0, ╧FF-╫HITE, ╔┼┼┼-488. ╟╨
- * ├┬═ ─9090 7.5 ═┬ ╚ARD ─RIVE, ─╧╙3.0, ╧FF-╫HITE, ╔┼┼┼-488. ╟╨
-
- ╘HE FOLLOWING MODEL HAS BEEN SAID TO BE IN EXISTENCE, THOUGH NO ONE
- HAS ONE ON HAND TO PROVE IT:
-
- * ├┬═ ─9065 7.5 ═┬ ╚ARD ─RIVE
-
- ┴ND THIS MODEL MAY NEVER HAVE MADE IT PAST THE PROTOTYPE STAGE:
- ├┬═ ─9062 ─UAL ─9065.
-
- ╤ $073) ╫HY DIDN'T BUYERS LIKE THE ORIGINAL ╨┼╘-64?
-
-
- ┴ $073) ╔T LOOKED JUST LIKE A OLD-STYLE ├-64. ╔T HAD A "HOME" COMPUTER
- LOOK THAT THE SCHOOLS DIDN'T CARE FOR. ╘HEY LIKED THE "BUSINESS"
- LOOK OF THE ╨┼╘ SERIES, SO ├OMMODORE PUT REFURBISHED AND NEW 64
- MOTHERBOARDS IN ╨┼╘ CASES AND SOLD THEM AS ╨┼╘ 64S. ╘HE REPACKAGING
- SUITED THE SCHOOLS.
-
- ╤ $074) ╧N A ╨┼╘ ╥EVISION 2 ╥╧═, WHAT WAS THE LARGEST SINGLE ARRAY SIZE THAT
- ┬┴╙╔├ COULD HANDLE?
-
-
- ┴ $074) ┴N ARRAY CAN HAVE A CUMULATIVE TOTAL OF 256 ELEMENTS. ╞OR SINGLE
- DIMENSION ARRAYS, THAT MEANS ─(0) TO ─(255), BUT A 2─ ARRAY CAN ONLY
- GO FROM ──(0,0) TO ──(1,127) ETC. ┴LL TYPES OF ARRAYS HAD THIS
- LIMITATION.
-
- ╤ $075) ╧N THE STOCK 1541, DATA IS TRANSMITTED ONE BIT AT A TIME. ╚OW MANY
- BITS ARE TRANSFERRED AT A TIME ON THE ├OMMODORE 1551 DISK DRIVE?
-
-
- ┴ $075) 3 BITS WERE TRANSMITTED AT A TIME. ╔ ASSUME THAT EACH BYTE HAD A
- PARITY BIT TACKED ON FOR ERROR DETECTION, SO IT WOULD HAVE TAKEN
- 3 TRANSFERS TO TRANSMIT A BYTE OF INFORMATION FROM THE DRIVES.
-
- ╤ $076) ╧N ALL ├OMMODORE FLOPPY DISK DRIVES, HOW FAST DOES THE DISK SPIN?
-
- ┴ $076) 300 ╥╨═.
-
- ╤ $077) ╒PON FIRST READING THE ├OMMODORE 1541 ┼RROR CHANNEL AFTER TURNING
- ON THE DISK DRIVE, WHAT ERROR NUMBER AND TEXT IS RETURNED?
-
- ┴ $077) 73, ├┬═ ─╧╙ ╓2.6 1541, 0, 0
-
- ╤ $078) ╫HAT ERROR NUMBER AND TEXT IS RETURNED ON A 1551?
-
- ┴ $078) 73, ├┬═ ─╧╙ ╓2.6╘─╔╙╦, 0, 0 ╬OTICE THAT THE NEW TEXT ╩╒╙╘ FITS!
-
- ╤ $079) ├OMMODORE PRINTERS ARE NORMALLY ASSIGNED TO DEVICE #4, BUT THEY
- CAN BE ALSO USED AS DEVICE #?
-
- ┴ $079) #5. ╘HE ├OMMODORE 1525 HAS A SWITCH TO DO THIS, BUT NOT ALL PRINTERS
- HAVE SUCH A SWITCH.
-
- ╤ $07┴) ╫HAT MICROPROCESSOR IS USED IN THE ├OMMODORE 1551 DISK DRIVE?
-
- ┴ $07┴) THE 6510╘. ╔T IS A SLIGHT VARIANT ON THE 6510 MICROPROCESSOR USED
- ON THE ├64. ╙OME SAY IT RUNS AT 2 ═╚Z, BUT THE SPECS DRIVES SPEC
- SHEET DOESN'T SAY.
-
- ╤ $07┬) ╫HEN THE ╓╔├-20 WAS DESIGNED, THE SERIAL PORT THROUGHPUT WAS ROUGHLY
- EQUIVALENT TO THE THROUGHPUT OF THE ╔┼┼┼-488 BUS? ╫HY ISN'T IT
- VERY FAST IN PRODUCTION ╓╔├S?
-
- ┴ $07┬) ╠ET'S GO BACK TO QUESTION $04╞:
-
- <BEGIN INSERT>
-
- ╤ $04╞) ╫HAT WAS THE PRIMARY REASON ├OMMODORE WENT TO A SERIAL BUS
- WITH THE INTRODUCTION OF THE ╓╔├-20?
-
-
- ┴ $04╞) ╩IM ┬UTTERFIELD SUPPLIED ME WITH THIS ONE:
- ┴S YOU KNOW, THE FIRST ├OMMODORE COMPUTERS USED THE ╔┼┼┼ BUS
- TO CONNECT TO PERIPHERALS SUCH AS DISK AND PRINTER. ╔
- UNDERSTAND THAT THESE WERE AVAILABLE ONLY FROM ONE SOURCE:
- ┬ELDEN CABLES. ┴ COUPLE OF YEARS INTO ├OMMODORE'S COMPUTER
- CAREER, ┬ELDEN WENT OUT OF STOCK ON SUCH CABLES (MILITARY
- CONTRACT? WHO KNOWS?). ╔N ANY CASE, ├OMMODORE WERE IN QUITE
- A FIX: THEY MADE COMPUTERS AND DISK DRIVES, BUT COULDN'T
- HOOK 'EM TOGETHER! ╙O ╘RAMIEL ISSUED THE ORDER: "╧N OUR NEXT
- COMPUTER, GET OFF THAT BUS. ═AKE IT A CABLE ANYONE CAN
- MANUFACTURE". ┴ND SO, STARTING WITH THE ╓╔├-20 THE SERIAL
- BUS WAS BORN. ╔T WAS INTENDED TO BE JUST AS FAST AS THE
- ╔┼┼┼-488 IT REPLACED.
- <END INSERT>
-
- ┴ND HERE IS WHAT ╩IM ┬UTTERFIELD FOLLOWED UP WITH:
- "╘ECHNICALLY, THE IDEA WAS SOUND: THE 6522 ╓╔┴ CHIP HAS A "SHIFT
- REGISTER" CIRCUIT THAT, IF TICKLED WITH THE RIGHT SIGNALS (DATA AND
- CLOCK) WILL CHEERFULLY COLLECT 8 BITS OF DATA WITHOUT ANY HELP FROM
- THE ├╨╒. ┴T THAT TIME, IT WOULD SIGNAL THAT IT HAD A BYTE TO BE
- COLLECTED, AND THE PROCESSOR WOULD DO SO, USING AN AUTOMATIC
- HANDSHAKE BUILT INTO THE 6522 TO TRIGGER THE NEXT INCOMING BYTE.
-
- ╘HINGS WORKED IN A SIMILAR WAY OUTGOING FROM THE COMPUTER, TOO.
- ╫E EARLY ╨┼╘/├┬═ FREAKS KNEW, FROM PLAYING MUSIC, THAT THERE WAS
- SOMETHING WRONG WITH THE 6522'S SHIFT REGISTER: IT INTERFERED WITH
- OTHER FUNCTIONS. ╘HE RULE WAS: TURN OFF THE MUSIC BEFORE YOU START
- THE TAPE! (╘HE SHIFT REGISTER WAS A POPULAR SOUND GENERATOR). ┬UT
- THE ├OMMODORE ENGINEERS, WHO ONLY MADE THE CHIP, DIDN'T KNOW THIS.
- ╒NTIL THEY GOT INTO FINAL CHECKOUT OF THE ╓╔├-20.
-
- ┬Y THIS TIME, THE ╓╔├-20 BOARD WAS IN MANUFACTURE. ┴ NEW CHIP COULD
- BE DESIGNED IN A FEW MONTHS (YES, THE SILICON GUYS HAD APPLICATION
- NOTES ABOUT THE PROBLEM, LONG SINCE), BUT IT WAS ╘╧╧ ╠┴╘┼!
-
- ┴ MAJOR SOFTWARE REWRITE HAD TO TAKE PLACE THAT CHANGED THE ╓╔├-20
- INTO A "BIT-CATCHER" RATHER THAN A "CHARACTER-CATCHER". ╔T CALLED FOR
- EIGHT TIMES AS MUCH WORK ON THE PART OF THE ├╨╒; AND UNLIKE THE SHIFT
- REGISTER PLAN, THERE WAS NO TIMING/HANDSHAKE SLACK TIME. ╘HE WHOLE
- THING SLOWED DOWN BY A FACTOR OF APPROXIMATELY 5 TO 6.
-
- ╫HEN THE 64 CAME OUT, THE PROBLEM ╓╔┴ 6522 CHIP HAD BEEN
- REPLACED BY THE ├╔┴ 6526. ╘HIS DID NOT HAVE THE SHIFT REGISTER
- PROBLEM WHICH HAD CAUSED TROUBLE ON THE ╓╔├-20, AND AT THAT TIME IT
- WOULD HAVE BEEN POSSIBLE TO RESTORE PLAN 1, A FAST SERIAL BUS. ╬OTE
- THAT THIS WOULD HAVE CALLED FOR A REDESIGN OF THE 1540 DISK DRIVE,
- WHICH ALSO USED A ╓╔┴. ┴S BEST ╔ CAN ESTIMATE - AND AN ARTICLE IN
- THE ╔┼┼┼ ╙PECTRUM MAGAZINE SUPPORTS THIS - THE MATTER WAS DISCUSSED
- WITHIN ├OMMODORE, AND IT WAS DECIDED THAT ╓╔├-20 COMPATIBILITY WAS
- MORE IMPORTANT THAN DISK SPEED. ╨ERHAPS THE PROSPECT OF A 1541
- REDESIGN WAS AN IMPORTANT PART OF THE DECISION, SINCE CURRENT
- INVENTORIES NEEDED TO BE TAKEN INTO ACCOUNT. ┬UT TO KEEP THE
- ├OMMODORE 64 AS A "BIT-BANGER", A NEW PROBLEM AROSE.
- ╘HE HIGHER-RESOLUTION SCREEN OF THE 64 (AS COMPARED TO THE ╓╔├-20)
- COULD NOT BE SUPPORTED WITHOUT STOPPING THE ├╨╒ EVERY ONCE IN A WHILE.
- ╘O BE EXACT: ┼VERY 8 SCREEN RASTER LINES (EACH LINE OF TEXT), THE ├╨╒
- HAD TO BE PUT INTO A ╫┴╔╘ CONDITION FOR 42 MICROSECONDS, SO AS TO
- ALLOW THE NEXT LINE OF SCREEN TEXT AND COLOR NYBBLES TO BE SWEPT INTO
- THE CHIP.(═ORE TIME WOULD BE NEEDED IF SPRITES WERE BEING USED).
- ┬UT THE BITS WERE COMING IN ON THE SERIAL BUS FASTER THAN THAT:
- A BIT WOULD COME IN ABOUT EVERY 20 MICROSECONDS! ╙O THE POOR ├╨╒,
- FROZEN FOR LONGER THAN THAT, WOULD MISS SOME SERIAL BITS COMPLETELY!
- ├OMMODORE'S SOLUTION WAS TO SLOW DOWN THE SERIAL BUS EVEN MORE.
- ╘HAT'S WHY THE ╓╔├-20 HAS A FASTER SERIAL BUS THAN THE 64, EVEN THOUGH
- THE 64 WAS CAPABLE, TECHNICALLY, OF RUNNING MANY TIMES FASTER.
-
- ╞AST DISK FINALLY CAME INTO ITS OWN WITH THE ├OMMODORE 128."
- ---╩IM
-
- ╤ $07├) ╧N ├OMMODORE COMPUTERS, HOW MUCH ╥┴═ IS SET ASIDE AS A TAPE BUFFER?
-
- ┴ $07├) 192 BYTES IS USED AS A TAPE BUFFER. ┬LOCKS OF DATA ON TAPE ARE 192
-
-
- ╤ $07─) ╧N ├OMMODORE COMPUTERS, MOST EVERY PERIPHERAL HAS A DEVICE NUMBER.
- ╫HAT IS THE DEVICE NUMBER OF THE SCREEN?
-
-
- ┴ $07─) #3
-
-
- ╤ $07┼) ╫HAT IS THE DEVICE NUMBER OF THE KEYBOARD?
-
-
- ┴ $07┼) #0
-
-
- ╤ $07╞) ├OMMODORE COMPUTERS USE 2'S-COMPLEMENT NOTATION TO REPRESENT INTEGERS.
- ╫HAT IS THE 2'S-COMPLEMENT HEX REPRESENTATION OF THE SIGNLE BYTE -1?
-
-
- ┴ $07╞) (╘HIS WAS NOT A ├OMMODORE SPECIFIC QUESTION) ├OMMODORE COMPUTERS
- USE THIS NOTATION TO REPRESENT INTEGER QUANTITIES. ╔N 2'S COMPLEMENT
- NOTATION, A -1 LOOKS LIKE 11111111(BINARY) OR $╞╞(HEX).
-
-
- ┼ND OF ├OMMODORE ╘RIVIA ┼DITION #8!
-
-
-
- ╩IM ┬RAIN
- BRAIN@MAIL.MSEN.COM
- 2306 ┬ ╚ARTLAND ╥OAD
- ╚ARTLAND, ═╔ 48353
- (810) 737-7300 X8528