The machine is also configured with a 2nd, exterior, floppy drive, which was related to the ribbon cable that connected the keyboard to the computer. The 5501 also comprises an async serial controller, which was overloaded to supply to services for the computer. Parallel and serial communications and a handful of programmable timers have been managed by the TMS 5501 I/O chip. As mentioned briefly earlier than, the 5501 has a single serial channel that normally operates at a maximum of 9600 bps. 3 would fire, issue an RST 3 instruction to the 8080. That routine would then drive one row of the keyboard, then learn that parallel port to sense which keys linked to that row had been depressed. There is no such thing as a reason why a few the I/O port ranges appear twice; it is simply incomplete decoding of the port handle bus, saving a bit of logic. If the CPU accesses the display RAM at the identical time the video era logic does, the CPU wins and there is a visible "tear" in the video stream. It means the info stream may need lengthy-time period DC content material, yet the recording medium is incapable of tracking it; it also implies that there are not any unlawful bit encodings, such that there aren`t any easy to tell apart encodings to use to sync to; it additionally means that the learn logic can not use AGC (automated achieve management) and must have an absolute threshold for distinguishing a one bit from a zero bit.



































The ensuing photograph was somewhat underexposed (slightly more so by comparison with the Kako flash on the 450), but nonetheless might be thought-about an appropriate photograph. While I have never examined this-- with 400-series cameras, you may be capable of `manually` modify the flash publicity your self at the digicam by changing the place of the Scene Selector and/or ASA dial to decide on the lens aperture. If you do not thoughts permanently altering your camera cosmetically, I suppose you could attach an accessory shoe to your digital camera`s body (using, say, small machine screws or maybe even epoxy). FCS views the disk as four hundred sectors, sector zero via sector 399. Sector 0 starts with a small descriptor indicating how many sectors are to be used for the disk directory, and in addition comprises a ten byte volume label. The Compucolor design relied on LSI chips as a lot as possible so as to fit into the small cabinet at a reasonable price. The predecessor of the Compucolor II was the ISC 8001, which originally used an 8-observe drive for storage. To avoid wasting money, Compucolor bought the raw drive mechanism from Wangco (later purchased by Siemens) and used their very own drive electronics. If there is a learn error, the only restoration mechanism is to retry the learn.



































Perhaps there`s some minor difference in the flash sync mechanism on these two cameras..? Because recordsdata are solely ever appended to the listing, saving FOO.BAS to disk, enhancing it a bit, then saving it again will result in two entries: FOO.BAS;1 and FOO.BAS;2. Since the shutter velocity is mounted when using the special flash plug, this could result in some added flexibility when using digital flash with such cameras. 268 Flashgun seems to end in underexposure. 268 Flashgun as meant for this camera. Flash brackets aren`t as easy to search out new as they as soon as have been, but ask at your native full-service camera retailer in the event that they`ve got an old one round you`ll be able to buy inexpensively. When searching for a bracket, nonetheless, be sure and measure the base of the bracket-- or, higher but, bring your digicam alongside-- many flash brackets aren`t lengthy enough to accomodate the width of a Polaroid pack digicam (particularly for the reason that tripod socket of those cameras is means over on the appropriate-hand side of the camera`s base).



































It will have been simple enough to initialize those CRTC registers from a table in ROM, shield control cable but the Compucolor design did not try this. Slots in the listing table are fully packed and searched in order. When the "plot" bit (bit 7) of the attribute byte was low, it indicated that the character byte was to be interpreted in line with the desk under. CP/M didn`t have this and thus it was just a software convention to in some way sign the final significant byte of the file, eg -Z in a text file. This perforated disc is present during all `normal` current mild exposures, so it`s interesting that removing it (thus letting extra mild hit the metering cell) actually resulted in overexposure with the digital flash. 268 flash by removing the blue flash shield. Ideally, A flash needs to be chosen that has an automated mode geared for about f/8.8 exposures at about ASA 80. If a manual flash is used (or an automatic flash is utilized in manual mode), then it is best to keep to across the calcualted `preferrred` distance for exposures at f/8.Eight with ASA 80 film. Because of this, during a FCS DELETE operation, the display screen is filled with colorful psychedelic rubbish, which is then cleared after the DELETE is done.