Macos Usan Hack MacOSX
Unlike the IBM PC, which uses 8 kB of system ROM for power-on self-test (POST) and basic input/output system (BIOS), the Mac ROM is significantly larger (64 kB) and holds key OS code. Much of the original Mac ROM was coded by Andy Hertzfeld, a member of the original Macintosh team. He was able to conserve precious ROM space by writing routines in assembly language code optimized with "hacks," or clever programming tricks. In addition to the ROM, he also coded the kernel, the Macintosh Toolbox, and some of the desktop accessories (DAs). The icons of the operating system, which represent folders and application software, were designed by Susan Kare, who later designed the icons for Microsoft Windows 3.0. Bruce Horn and Steve Capps wrote the Macintosh Finder, as well as a number of Macintosh system utilities.
Macos usan hack MacOSX
Digitizing images and video was a tricky job in the mid-1980s. Flatbed scanners were few and far between. Consumer-oriented digital cameras were still a decade away. If you needed to capture an image onto a computer, the usual way it was done involved an NTSC video camera. A digitizer box between the camera and the computer captured a single NTSC video frame and converted it to a bit-stream to be interpreted by the computer.Much like a television production or a photographer's studio, a tripod, lighting setup, and backdrop, were usually all required. In the world of personal computers, digitized images were rare, and memorable because of their rarity.The Macintosh team experimented with digitizers on the Macintosh in 1983 and 1984. Susan Kare's famous "Japanese woodcut" image began as a digitized image that she retouched in MacPaint.When Andy Hertzfeld decided to take a leave from Apple in spring 1984, shortly after the release of Macintosh, he didn't rest on his heels. Instead he went to work for Thunderware, writing the software for a new digitizer called Thunderscan.Thunderscan, first announced in fall 1984, was an ingenious hack. It replaced the ribbon cartridge of an Imagewriter printer with a scanning cartridge. A small digitizer box interfaced the scanner with the Macintosh through the serial port. Any media that could survive a roll through the Imagewriter could be digitized on the Macintosh. When the ImageWriter II came out in 1986, Thunderscan was modified to work with it too.Setting Up ThunderscanThunderscan takes a bit of preparation to use, and the instructions differ depending on if you're using an Imagewriter or ImageWriter II. Let's take a look at the contents of the Thunderscan box, shown in the photo below.At top left is the Thunderscan digitizing cartridge. This replaces the ribbon in your printer. Next to it is an adapter needed for the Macintosh Plus serial port. The digitizer needs power from the serial port, but with the Mac Plus, the serial ports are no longer powered. This adapter borrows from the floppy disk port instead. At top right, the rectangular black object is a "scan key" for the original Imagewriter. It lets you work the Imagewriter with its lid off. At bottom right is the Thunderscan interface box, which connects both printer and digitizer to the Mac's serial port.Contents of the Thunderscan boxNo matter which printer, you need to remove the ribbon cartridge and replace it with the Thunderscan digitizing cartridge. You will notice a red "eye" at one end. This eye is off-center and is angled slightly. Don't touch it or attempt to adjust it. It's supposed to be skewed this way. A knob at the opposite end of the cartridge will cause the eye to move in or out, which adjusts the focus.With the digitizer cartridge snapped into place, you will notice, probably for the first time, just as I did, that there is a small circular hole in the plastic paper guide of the ImageWriter's print carriage. It seems like this hole was put there in anticipation of the Thunderscan! I don't know the story behind this convenient hole, but the red eye of the digitizer needs to be able to peep through it.The red "eye" of the digitizer is supposed to be off-center and crooked. Don't try to fix it!The next step is to remove the printer's cover. For the original Imagewriter, you need to place the plastic "scan key" near the cover sensor so that the printer thinks the cover is actually in place.With an ImageWriter II, you are supposed to remove the smoked plastic window. This is a delicate job which must be done slowly and with care, as your 30 year-old plastics are now quite brittle.You are supposed to route the cable from the digitizer cartridge so that it does not interfere with the motion of the print carriage. Optionally, you can apply a strip of white tape at both ends of the large black roller to allow the Thunderscan software to detect the edge of the page. Or if your pages have white margins, the tape isn't needed.Next, connect the digitizer's cable to the Thunderscan interface box, then connect the printer cable to this box too. Then connect the interface box's white DE-9 cable to the Macintosh printer port. If you're using a Mac Plus, you will have to use the adapter which takes power from the floppy port.It's quite a contraption, and Thunderscan is a definitely a hack, in every sense of the word!Preparing to ScanGetting good results from Thunderscan takes some practice. Your first several attempts will probably cause you great doubts about the Thunderscan's abilities. But rest assured, with some patience and practice, you can get decent results.First of all, you ought to practice with the locomotive tutorial image, if you have it. This is printed on heavy paper and is a "known-good" image that will scan well. Load it into the ImageWriter printer as usual, with the locomotive right side up.Next you need to adjust focus. In the Thunderscan application, choose Focus from the Scanner menu. In the dialog that appears will be a number at the bottom. The higher this number, the better. It should ideally be between 32 to 40-something. If it's less than 30, you have a problem.The red eye of the digitizer should be over the lightest, and therefore most reflective, part of the image that you're scanning.To adjust focus, you turn the knob on top of the scanner cartridge. With the ImageWriter II, you have to remove the lid to get to this knob. Adjust the knob until you get the highest number. Alternatively, you can also move the paper-thickness lever.If you can't get this number into at least the 30s, then probably the red beam of the eye is not shining through the small circular hole of the plastic paper guide. To the right of the black printhead is a plastic Archimedes' screw. Turn this either way to raise or lower the cartridge deck as needed so the red beam is shining through the hole and on to the paper.In the photo below, the white arrow indicates the red beam of the digitizing eye. The focus knob is called out by 1 and the archimedes' screw to adjust deck height is 2.Close-up of the Thunderscan digitizing cartridgeScanningIt will take several minutes to scan an image at 100% magnification, which equates to 72 dpi. The preview image will update every few lines. It should resemble the image in the scanner. If it's a dark shadowy mess, barely recognizable, then most likely the problem is that the red beam from the eye is not properly shining through the hole.Here is my scan of the locomotive image in-progress:After the scan is complete, compare the original and what you got on the screen to see how they match. The locomotive image, which was probably an engraving, was chosen specifically because it produces a clean scan.Original at right compared with the 1-bit scan on the Mac's screenThis digitized image is my fourth or fifth attempt at scanning. If you don't get a clean scan like this, keep trying. The Thunderscan is fiddly.If you like the image that you got, you can save it to a MacPaint file and do some more touchup work to it in MacPaint. You can also do some correction within Thunderscan.Color ScanningNow let's scan a glossy color photo from a magazine. I chose a pleasing image of a gate with an interesting pattern, surrounded by red brick. Here is the page to be scanned:Increasing the scan magnification will increase resolution. 200% magnification will yield a 144 dpi image. I scanned this image at slightly above 100%. Here it is in the ImageWriter II, the scanning in progress:After more than 10 minutes, the scan is complete, and I can look at the 1-bit image on the screen. Notice the ragged edges. I will discuss this deficiency later on. The text at right is illegible. A higher magnification (resolution) would probably yield legible text.You would never know it from the Mac's 1-bit screen, but the Thunderscan is capable of grayscale digitizing, and saves gray tone information in its native file format.LimitationsAfter you have scanned a few images, limitations of the Thunderscan system will be apparent to you. Most of these limitations are due to the ImageWriter printer, and are probably exacerbated by the age of these printers. To get a crisp scan, it is necessary for the carriage to stop and start very precisely as it sweeps left and right across the original image. If not, the edges of the scanned image will be ragged instead of straight.Aging motors, belts, and lubricants all contribute to this degradation of image quality. The carriage needs to travel at a constant velocity across the original image. Otherwise, tearing of the digitized image will result where the carriage digitizer slowed a bit. The two images that I scanned, shown below, exhibit both symptoms of ragged edges and tearing.Completed ScansHere are two completed scans. You can export scans to TIFF or EPS (encapsulated PostScript) formats. Thunderscan's TIFF implementation uses a non-standard compression scheme. It supposedly encodes the grayscale information, but I was not able to see grayscale in Adobe Photoshop or Apple Preview on Mac OS X. I only got the bitmapped image. I did not try EPS. Perhaps EPS would show gray tones.Both images have been saved in PNG format with no further manipulation to the bitmap. Both were scanned at more than 100% magnification.This image of a girl in a lounge chair was scanned at a higher magnification than the gates image. Note the horizontal tearing, most prominent through the star-burst wall clock above the girl's head.These two images show ragged left and right edges, caused by the ImageWriter II's carriage not stopping at precisely the same place on each line. If I had an ImageWriter II in better shape, perhaps I would get crisper scans.The Thunderscan is a decent digitizer which is hampered by hacking it on to an ImageWriter printer. The software is good. Scanning is slow, but only due to the printer being slow. No doubt many thousands of images were digitized on a Thunderscan, and you can get respectable images from it with some patience and care.Here we are at the conclusion of yet another Mac 512K Blog article. In the next one, I will share some of my tips and experience in imaging old Mac disks with Disk Copy 4.2. The Mac 512K Blog wrote:This blog chronicles the Macintosh 512K and my projects with it. We will test software, fix hardware, program it, hack it, and generally take the 512K Macintosh to its limits.Do leave any feedback you may have, either to my email email@example.com or by posting a comment to this article.