Defect Mac OS

1. Defect Masking
2. Defect Mac Os 11

As wonderful as Mac OS X is, it has a grave defect that can have an immediate adverse impact on the computer's usability: the way it translates mouse motion into pointer movement. For many users, moving the mouse feels unnatural because of the peculiar way that Mac OS X performs that translation. In industry parlance, the translation is called the 'mouse acceleration curve.' What is a mouse acceleration curve, and how is its implementation problematic under Mac OS X?

Mac OS X 10.5 'Leopard' (or later) Readme.txt macrodemomaclinux.zip: 23.759 Mb: Linux (Intel 32-bit) Readme.txt macrodemomaclinux.zip: 23.759 Mb: Web Server (Intranet) Readme.txt macrodemoserver.zip: 23.759 Mb. Nov 20, 2020 Shut down your Mac. Disconnect all external devices except keyboard, mouse, display, Ethernet connection (if applicable), and connection to AC power. Make sure that your Mac is on a hard, flat, stable surface with good ventilation.

Speedy Gonzales — Mouse movement cannot be translated into pointer movement at a simple one-to-one ratio. If it were, you'd need to move the mouse 17 inches (43 cm) across your desk to move the pointer across the diagonal of a 17-inch monitor. That would be highly impractical because you'd need a tremendous amount of space to move the mouse around, and your arm would tire quickly. (Either that, or you'd have to constantly pick the mouse up and put it back down, which would also be both tedious and wearisome, though possibly amusing to watch.)

Can you compensate by increasing the ratio so that, say, the pointer moves three inches for every inch the mouse moves? That simply trades one problem for another one. For example, on most displays, even at lower resolutions, the centers of the close and minimize buttons at the top of a standard window are typically about .25 inches (6.4 mm) apart (at higher resolutions, it's even less than that). With a three-to-one pointer-to-mouse movement ratio, then, you'd have to move your mouse about .083 inches (2.1 mm), no more, no less, to move from the center of the close button to get to the center of the minimize button. That's roughly the thickness of three credit cards. Moving a mouse with such precision is difficult for most people, andif it were regularly required, it would make the computer cumbersome to use. So a simple 'X-to-one' acceleration ratio won't work because if the value of X were too low, you'd still need lots of space to move the mouse around, but if the value of X were too high, precise pointer movement would be impossible.

The solution is for the operating system to use both concepts: a higher X-to-one ratio for faster mouse movement, enabling the user to move the pointer across the screen quickly with little use of desk space, and a lower X-to-one ratio for slower mouse movement, enabling the user to move the pointer precisely without needing to be fantastically precise in moving the mouse.

With this solution in place, users get the best of both worlds. If a user is moving the mouse very slowly – say, doing detailed work touching up a photo – the mouse-to-pointer ratio might be one-to-one (or even less than one-to-one), enabling precision movement with ease. Conversely, if the user then starts to move the mouse more quickly, wanting to jump to the other side of the screen, the X-to-one ratio changes dynamically, increasing as the user continues to increase the mouse's speed, until it reaches the other end of the X-to-one ratio, which might be as much as nine- or ten-to-one. Finally, as the user instinctively starts to slow the mouse down as the pointer nears the desired target, the operating system reverses the process,gradually decreasing the ratio once more and enabling the user to place the pointer precisely at the desired spot. (The math behind all of this is quite complicated. You may never look at your mouse the same way again.) The whole process makes it possible for the user to move the pointer from the photo he's touching up in the lower left of the screen to an icon in the upper right of the screen by moving the mouse only a short distance. Donut roll (sumguy67) mac os.

If you were to take a sheet of graph paper and create a standard X-Y coordinate system – remember high school algebra? – with X representing the speed of the pointer and Y representing the speed of the mouse, and then map the ratio conversion process onto that graph, you'd end up with a sloping line, moving upward at first, and then flattening out with greater values of X. This line is called the 'mouse acceleration curve.'

Sharp Curves Ahead — So what's wrong with Mac OS X's mouse acceleration curve? Simply put, it's the wrong shape. For mouse motion to feel natural (at least for most people), the curve has to start by moving upward fairly moderately, then gradually flattening out as the value of X increases. Mac OS X's, curve, however, starts off by being too steep, staying too steep for too long, and then flattening out too abruptly. In practical terms this means that, frequently, as a user tries to use the mouse to move the pointer from point A to point B, the pointer motion feels sluggish. The user then tries to compensate for the sluggishness by moving the mouse faster, and the pointer suddenly goes flying across thescreen and overshoots point B. A comfortable and useful curve is actually shaped like a curve. Mac OS X's curve, however, is shaped more like a cliff.

It wasn't always this way. Under Mac OS 9 and earlier, the curve was different and provided more natural mouse behavior. Then, for some reason, Apple apparently decided to fix something that wasn't broken and changed the curve. They made no announcement of the change and, to the best of my knowledge, it does not appear anywhere in their technical documentation. (Microsoft, conversely, explains how the Windows XP mouse acceleration curve works on a publicly accessible Web page.) For this reason, most people don't know about the change and are wondering 'why the mouse feels funny' because they don't understand the esoteric details of the mouse acceleration curve. (And who can blame them? It's anything but simple arithmetic!)

I was one such person myself for quite some time, experimenting with different mice and a variety of mouse pads and other surfaces, trying to figure out how I could get the mouse to 'work right again.' It was only after many months of Googling on a variety of search terms that I finally found out about acceleration curves and learned that Apple had quietly changed theirs. I was fortunate in that I had several years of experience with the Classic Mac OS that told me there actually was something that needed to be fixed. People who have only started using the Mac in more recent years have no such advantage.

The unnatural motion of the new curve is troublesome for many users. User 'Sludge' on the MacSlash Web site, for example, complains, 'I can't believe how horrible mice feel on OS X compared to XP and Linux/XFree86.' Scott Moschella of PlasticBugs.com opines, '[T]he mouse acceleration…makes OS X's mouse tracking feel like you're mousing through mud,' referring to how the low end of the curve is too steep for too long.

Of course, not all users have this complaint. Some say they actually prefer the new pointer behavior, and some even claim they don't notice any difference. For those who do have trouble with the new curve, though, it's highly problematic – often in ways beyond just the difficulty in getting the pointer to move to the desired location.

When mouse movement feels unnatural, the user may subconsciously try to use hand and wrist muscles to compensate. At best, that's uncomfortable. At worst, it can be painful. In my own case, my wrist starts to cramp after only a moment or two. After about 20 minutes, most of my forearm is in extreme pain, and I have to stop using the mouse altogether.

Over time, users with this type of difficulty using the mouse can suffer from the permanent damage known as an RSI (repetitive stress injury). I am one such sufferer. An anonymous user on MacSlash rails about 'the RSI-inducing unpredictable madness that is the Mac mouse acceleration curve.' And on LifeHacker.com, user 'PhotoHobo' complains, 'One of my biggest annoyances with OS X is the horrible mouse acceleration. As someone who is constantly battling RSI, I find this intolerable.' Web searches find a number of other users voicing similar opinions and having similar difficulties.

Realigning Your Curves — So the problem is certainly real and immediate – at least for some of us – but can anything actually be done about it? Nuclear disaster with little bit of fault cause tesla mac os. There is no setting in Mac OS X itself to modify the acceleration curve. Sometimes, well-meaning users suggest modifying the Tracking Speed setting in the Keyboard & Mouse pane in System Preferences, but that doesn't provide a complete solution. The problem isn't speed, per se, but the acceleration curve. Changing the tracking speed does not change the shape of that curve. It just makes the whole curve smaller or larger, rather like using a telephoto lens (or a wide angle lens) to take a photograph of the same cliff from the same location.

Apple has left a void, then, in Mac OS X's settings. Fortunately, many third parties have tried to fill that void, and most do the job quite admirably. For example, several mouse manufacturers, such as Kensington, include their own mouse drivers and software that can be configured to override Mac OS X's mouse acceleration curve. The only drawback is that the software is usually specific to the hardware.

For those who already have mice that they don't wish to replace, there are other solutions, each with advantages over the others. MouseFix (freeware) is a simple program that changes some of the numbers used in Mac OS X's mouse driver in an attempt to make the curve more natural. However, it can be difficult to install for the non-technically inclined, and its presets are not customizable.

USB Overdrive ($20) is shareware with no trial period, and it offers an extensive variety of options for configuring mouse behavior, as well as the behavior of other USB devices. You can even configure it so that the mouse will behave differently depending on which application you're using. Its chief drawback, as the name implies, is that it supports only USB devices – if you use a Bluetooth mouse, you're out of luck. (The author, Alessandro Levi Montalcini, says that Bluetooth support is coming, but offers no time frame.)

SteerMouse ($20) is also shareware that offers a wide variety of customization options for mouse behavior, and unlike USB Overdrive, SteerMouse supports Bluetooth mice. Its main disadvantage is that it was designed with Apple's Mighty Mouse in mind – it does work with other mice, but support may be more limited. Also, the trial period is only 15 days, which may not be long enough to fully explore the software, because finding the most comfortable settings can take a while. I ultimately chose USB Overdrive over SteerMouse for this reason. SteerMouse expired before I became comfortable with it, whereas USB Overdrive, having no expiration date, afforded me ample opportunity to find the mousesettings that worked best for me.

Defect Masking

Hopefully, Apple will realize that changing the mouse acceleration curve was a mistake and revert to the old one. Better yet would be to add a setting to the Keyboard & Mouse preference pane to enable the user to configure the acceleration curve as well as the speed. The likelihood of that is anyone's guess, but in the meantime, we can save our hands, our wrists, and our sanity by having a clear understanding of what the problem is and working around it with third-party solutions.

Mac OS X, as we all know, is the Ferrari of operating systems. Unfortunately, the steering has a design defect, but with a little mechanical effort, we can modify it while we're waiting and hoping for the engineers to recognize the problem and fix it.

[Parrish S. Knight is a systems administrator for an IT consulting firm in the greater DC area. His interests include politics, film, fantasy, and science fiction. In addition to getting the word out about Mac OS X's mouse problems, his causes include activism in autistic advocacy and civil liberties.]

The Macintosh II is a personal computer designed, manufactured, and sold by Apple Computer from March 1987 to January 1990. Based on the Motorola 68020 32-bit CPU, it is the first Macintosh supporting color graphics. When introduced, a basic system with monitor and 20 MB hard drive cost US$5,498 Han river project 2020 mac os. (equivalent to $12,373 in 2019). With a 13-inch color monitor and 8-bit display card the price was around US$7,145 (equivalent to $16,079 in 2019).^[1] This placed it in competition with workstations from Silicon Graphics, Sun Microsystems, and Hewlett-Packard.

The Macintosh II was the first computer in the Macintosh line without a built-in display; a monitor rested on top of the case like the IBM PC and Amiga 1000. It was designed by hardware engineersMichael Dhuey (computer) and Brian Berkeley (monitor) and industrial designerHartmut Esslinger (case).

Eighteen months after its introduction, the Macintosh II was updated with a more powerful CPU and sold as the Macintosh IIx. In early 1989, the more compact Macintosh IIcx was introduced at a price similar to the original Macintosh II, and by the beginning of 1990 sales stopped altogether. Motherboard upgrades to turn a Macintosh II into a IIx or Macintosh IIfx were offered by Apple.

Development[edit]

Two common criticisms of the Macintosh from its introduction in 1984 were the closed architecture and lack of color; rumors of a color Macintosh began almost immediately.^[2]

The Macintosh II project was begun by Dhuey and Berkeley during 1985 without the knowledge of Apple co-founder and Macintosh division head Steve Jobs, who opposed expansion slots and color, on the basis that the former complicated the user experience and the latter did not conform to WYSIWYG—color printers were not common.^[3] He instead wanted higher-resolution monochrome displays.^[4]

Initially referred to as 'Little Big Mac', the Macintosh II was codenamed 'Milwaukee' after Dhuey's hometown, and later went through a series of new names. After Jobs was fired from Apple in September 1985, the project could proceed openly.

The Macintosh II was introduced at the AppleWorld 1987 conference in Los Angeles,^[5] with low-volume initial shipments starting two months later.^[6] Retailing for US $5,498,^[7] the Macintosh II was the first modular Macintosh model, so called because it came in a horizontal desktop case like many IBM PC compatibles of the time. Previous Macintosh computers use an all-in-one design with a built-in black-and-white CRT.

The Macintosh II has drive bays for an internal hard disk (originally 40 MB or 80 MB) and an optional second floppy disk drive. It, along with the Macintosh SE, was the first Macintosh to use the Apple Desktop Bus (ADB) introduced with the Apple IIGS for keyboard and mouse interface.

The primary improvement in the Macintosh II was Color QuickDraw in ROM, a color version of the graphics routines. Color QuickDraw can handle any display size, up to 8-bit color depth, and multiple monitors. Because Color QuickDraw is included in the Macintosh II's ROM and relies on 68020 instructions, earlier systems could not be upgraded to display color.

In September 1988, shortly before the introduction of the Macintosh IIx, Apple increased the list price of the Macintosh II by roughly 20%.^[8]

Hardware[edit]

CPU: The Macintosh II is built around the Motorola 68020 processor operating at 16 MHz, teamed with a Motorola 68881floating point unit. The machine shipped with a socket for an MMU, but the 'Apple HMMU Chip' (VLSI VI475 chip) was installed that did not implement virtual memory (instead, it translated 24-bit addresses to 32-bit addresses for the Mac OS, which would not be 32-bit clean until System 7).

Memory: The standard memory was 1 megabyte, expandable to 8 MB.^[9] The Mac II had eight 30-pin SIMMs, and memory was installed in groups of four (called 'Bank A' and 'Bank B').

The original Macintosh II did not have a PMMU by default. It relied on the memory controller hardware to map the installed memory into a contiguous address space. This hardware had the restriction that the address space dedicated to bank A must be larger than those of bank B. Though this memory controller was designed to support up to 16MB 30-pin SIMMs for up to 128MB of RAM, the original Macintosh II ROMs had problems limiting the amount of RAM that can be installed to 8MB. The Macintosh IIx ROMs that also shipped with the FDHD upgrade fixed this problem, though still do not have a 32-bit Memory Manager and cannot boot into 32-bit addressing mode under Mac OS (without the assistance of MODE32).^[10]MODE32 contained a workaround that allowed larger SIMMs to be put in Bank B with the PMMU installed. In this case, the ROMs at boot think that the computer has 8MB or less of RAM. MODE32 then reprograms the memory controller to dedicate more address space to Bank A, allowing access to the additional memory in Bank B. Since this makes the physical address space discontiguous, the PMMU is then used to remap the address space into a contiguous block.

Graphics: The Macintosh II includes a graphics card that supports a true-color 16.7 million color palette^[11] and was available in two configurations: 4-bit and 8-bit. The 4-bit model supports 16 colors on a 640×480 display and 256 colors (8-bit video) on a 512×384 display, which means that VRAM was 256 KB. The 8-bit model supports 256-color video on a 640×480 display, which means that VRAM was 512 KB in size. With an optional RAM upgrade (requiring 120ns DIP chips), the 4-bit version supports 640×480 in 8-bit color.^[12] The video card does not include hardware acceleration of drawing operations.

If you were to take a sheet of graph paper and create a standard X-Y coordinate system – remember high school algebra? – with X representing the speed of the pointer and Y representing the speed of the mouse, and then map the ratio conversion process onto that graph, you'd end up with a sloping line, moving upward at first, and then flattening out with greater values of X. This line is called the 'mouse acceleration curve.'

Sharp Curves Ahead — So what's wrong with Mac OS X's mouse acceleration curve? Simply put, it's the wrong shape. For mouse motion to feel natural (at least for most people), the curve has to start by moving upward fairly moderately, then gradually flattening out as the value of X increases. Mac OS X's, curve, however, starts off by being too steep, staying too steep for too long, and then flattening out too abruptly. In practical terms this means that, frequently, as a user tries to use the mouse to move the pointer from point A to point B, the pointer motion feels sluggish. The user then tries to compensate for the sluggishness by moving the mouse faster, and the pointer suddenly goes flying across thescreen and overshoots point B. A comfortable and useful curve is actually shaped like a curve. Mac OS X's curve, however, is shaped more like a cliff.

It wasn't always this way. Under Mac OS 9 and earlier, the curve was different and provided more natural mouse behavior. Then, for some reason, Apple apparently decided to fix something that wasn't broken and changed the curve. They made no announcement of the change and, to the best of my knowledge, it does not appear anywhere in their technical documentation. (Microsoft, conversely, explains how the Windows XP mouse acceleration curve works on a publicly accessible Web page.) For this reason, most people don't know about the change and are wondering 'why the mouse feels funny' because they don't understand the esoteric details of the mouse acceleration curve. (And who can blame them? It's anything but simple arithmetic!)

I was one such person myself for quite some time, experimenting with different mice and a variety of mouse pads and other surfaces, trying to figure out how I could get the mouse to 'work right again.' It was only after many months of Googling on a variety of search terms that I finally found out about acceleration curves and learned that Apple had quietly changed theirs. I was fortunate in that I had several years of experience with the Classic Mac OS that told me there actually was something that needed to be fixed. People who have only started using the Mac in more recent years have no such advantage.

The unnatural motion of the new curve is troublesome for many users. User 'Sludge' on the MacSlash Web site, for example, complains, 'I can't believe how horrible mice feel on OS X compared to XP and Linux/XFree86.' Scott Moschella of PlasticBugs.com opines, '[T]he mouse acceleration…makes OS X's mouse tracking feel like you're mousing through mud,' referring to how the low end of the curve is too steep for too long.

Of course, not all users have this complaint. Some say they actually prefer the new pointer behavior, and some even claim they don't notice any difference. For those who do have trouble with the new curve, though, it's highly problematic – often in ways beyond just the difficulty in getting the pointer to move to the desired location.

When mouse movement feels unnatural, the user may subconsciously try to use hand and wrist muscles to compensate. At best, that's uncomfortable. At worst, it can be painful. In my own case, my wrist starts to cramp after only a moment or two. After about 20 minutes, most of my forearm is in extreme pain, and I have to stop using the mouse altogether.

Over time, users with this type of difficulty using the mouse can suffer from the permanent damage known as an RSI (repetitive stress injury). I am one such sufferer. An anonymous user on MacSlash rails about 'the RSI-inducing unpredictable madness that is the Mac mouse acceleration curve.' And on LifeHacker.com, user 'PhotoHobo' complains, 'One of my biggest annoyances with OS X is the horrible mouse acceleration. As someone who is constantly battling RSI, I find this intolerable.' Web searches find a number of other users voicing similar opinions and having similar difficulties.

Realigning Your Curves — So the problem is certainly real and immediate – at least for some of us – but can anything actually be done about it? Nuclear disaster with little bit of fault cause tesla mac os. There is no setting in Mac OS X itself to modify the acceleration curve. Sometimes, well-meaning users suggest modifying the Tracking Speed setting in the Keyboard & Mouse pane in System Preferences, but that doesn't provide a complete solution. The problem isn't speed, per se, but the acceleration curve. Changing the tracking speed does not change the shape of that curve. It just makes the whole curve smaller or larger, rather like using a telephoto lens (or a wide angle lens) to take a photograph of the same cliff from the same location.

Apple has left a void, then, in Mac OS X's settings. Fortunately, many third parties have tried to fill that void, and most do the job quite admirably. For example, several mouse manufacturers, such as Kensington, include their own mouse drivers and software that can be configured to override Mac OS X's mouse acceleration curve. The only drawback is that the software is usually specific to the hardware.

For those who already have mice that they don't wish to replace, there are other solutions, each with advantages over the others. MouseFix (freeware) is a simple program that changes some of the numbers used in Mac OS X's mouse driver in an attempt to make the curve more natural. However, it can be difficult to install for the non-technically inclined, and its presets are not customizable.

USB Overdrive ($20) is shareware with no trial period, and it offers an extensive variety of options for configuring mouse behavior, as well as the behavior of other USB devices. You can even configure it so that the mouse will behave differently depending on which application you're using. Its chief drawback, as the name implies, is that it supports only USB devices – if you use a Bluetooth mouse, you're out of luck. (The author, Alessandro Levi Montalcini, says that Bluetooth support is coming, but offers no time frame.)

SteerMouse ($20) is also shareware that offers a wide variety of customization options for mouse behavior, and unlike USB Overdrive, SteerMouse supports Bluetooth mice. Its main disadvantage is that it was designed with Apple's Mighty Mouse in mind – it does work with other mice, but support may be more limited. Also, the trial period is only 15 days, which may not be long enough to fully explore the software, because finding the most comfortable settings can take a while. I ultimately chose USB Overdrive over SteerMouse for this reason. SteerMouse expired before I became comfortable with it, whereas USB Overdrive, having no expiration date, afforded me ample opportunity to find the mousesettings that worked best for me.

Defect Masking

Hopefully, Apple will realize that changing the mouse acceleration curve was a mistake and revert to the old one. Better yet would be to add a setting to the Keyboard & Mouse preference pane to enable the user to configure the acceleration curve as well as the speed. The likelihood of that is anyone's guess, but in the meantime, we can save our hands, our wrists, and our sanity by having a clear understanding of what the problem is and working around it with third-party solutions.

Mac OS X, as we all know, is the Ferrari of operating systems. Unfortunately, the steering has a design defect, but with a little mechanical effort, we can modify it while we're waiting and hoping for the engineers to recognize the problem and fix it.

[Parrish S. Knight is a systems administrator for an IT consulting firm in the greater DC area. His interests include politics, film, fantasy, and science fiction. In addition to getting the word out about Mac OS X's mouse problems, his causes include activism in autistic advocacy and civil liberties.]

The Macintosh II is a personal computer designed, manufactured, and sold by Apple Computer from March 1987 to January 1990. Based on the Motorola 68020 32-bit CPU, it is the first Macintosh supporting color graphics. When introduced, a basic system with monitor and 20 MB hard drive cost US$5,498 Han river project 2020 mac os. (equivalent to $12,373 in 2019). With a 13-inch color monitor and 8-bit display card the price was around US$7,145 (equivalent to $16,079 in 2019).^[1] This placed it in competition with workstations from Silicon Graphics, Sun Microsystems, and Hewlett-Packard.

The Macintosh II was the first computer in the Macintosh line without a built-in display; a monitor rested on top of the case like the IBM PC and Amiga 1000. It was designed by hardware engineersMichael Dhuey (computer) and Brian Berkeley (monitor) and industrial designerHartmut Esslinger (case).

Eighteen months after its introduction, the Macintosh II was updated with a more powerful CPU and sold as the Macintosh IIx. In early 1989, the more compact Macintosh IIcx was introduced at a price similar to the original Macintosh II, and by the beginning of 1990 sales stopped altogether. Motherboard upgrades to turn a Macintosh II into a IIx or Macintosh IIfx were offered by Apple.

Development[edit]

Two common criticisms of the Macintosh from its introduction in 1984 were the closed architecture and lack of color; rumors of a color Macintosh began almost immediately.^[2]

The Macintosh II project was begun by Dhuey and Berkeley during 1985 without the knowledge of Apple co-founder and Macintosh division head Steve Jobs, who opposed expansion slots and color, on the basis that the former complicated the user experience and the latter did not conform to WYSIWYG—color printers were not common.^[3] He instead wanted higher-resolution monochrome displays.^[4]

Initially referred to as 'Little Big Mac', the Macintosh II was codenamed 'Milwaukee' after Dhuey's hometown, and later went through a series of new names. After Jobs was fired from Apple in September 1985, the project could proceed openly.

The Macintosh II was introduced at the AppleWorld 1987 conference in Los Angeles,^[5] with low-volume initial shipments starting two months later.^[6] Retailing for US $5,498,^[7] the Macintosh II was the first modular Macintosh model, so called because it came in a horizontal desktop case like many IBM PC compatibles of the time. Previous Macintosh computers use an all-in-one design with a built-in black-and-white CRT.

The Macintosh II has drive bays for an internal hard disk (originally 40 MB or 80 MB) and an optional second floppy disk drive. It, along with the Macintosh SE, was the first Macintosh to use the Apple Desktop Bus (ADB) introduced with the Apple IIGS for keyboard and mouse interface.

The primary improvement in the Macintosh II was Color QuickDraw in ROM, a color version of the graphics routines. Color QuickDraw can handle any display size, up to 8-bit color depth, and multiple monitors. Because Color QuickDraw is included in the Macintosh II's ROM and relies on 68020 instructions, earlier systems could not be upgraded to display color.

In September 1988, shortly before the introduction of the Macintosh IIx, Apple increased the list price of the Macintosh II by roughly 20%.^[8]

Hardware[edit]

CPU: The Macintosh II is built around the Motorola 68020 processor operating at 16 MHz, teamed with a Motorola 68881floating point unit. The machine shipped with a socket for an MMU, but the 'Apple HMMU Chip' (VLSI VI475 chip) was installed that did not implement virtual memory (instead, it translated 24-bit addresses to 32-bit addresses for the Mac OS, which would not be 32-bit clean until System 7).

Memory: The standard memory was 1 megabyte, expandable to 8 MB.^[9] The Mac II had eight 30-pin SIMMs, and memory was installed in groups of four (called 'Bank A' and 'Bank B').

The original Macintosh II did not have a PMMU by default. It relied on the memory controller hardware to map the installed memory into a contiguous address space. This hardware had the restriction that the address space dedicated to bank A must be larger than those of bank B. Though this memory controller was designed to support up to 16MB 30-pin SIMMs for up to 128MB of RAM, the original Macintosh II ROMs had problems limiting the amount of RAM that can be installed to 8MB. The Macintosh IIx ROMs that also shipped with the FDHD upgrade fixed this problem, though still do not have a 32-bit Memory Manager and cannot boot into 32-bit addressing mode under Mac OS (without the assistance of MODE32).^[10]MODE32 contained a workaround that allowed larger SIMMs to be put in Bank B with the PMMU installed. In this case, the ROMs at boot think that the computer has 8MB or less of RAM. MODE32 then reprograms the memory controller to dedicate more address space to Bank A, allowing access to the additional memory in Bank B. Since this makes the physical address space discontiguous, the PMMU is then used to remap the address space into a contiguous block.

Graphics: The Macintosh II includes a graphics card that supports a true-color 16.7 million color palette^[11] and was available in two configurations: 4-bit and 8-bit. The 4-bit model supports 16 colors on a 640×480 display and 256 colors (8-bit video) on a 512×384 display, which means that VRAM was 256 KB. The 8-bit model supports 256-color video on a 640×480 display, which means that VRAM was 512 KB in size. With an optional RAM upgrade (requiring 120ns DIP chips), the 4-bit version supports 640×480 in 8-bit color.^[12] The video card does not include hardware acceleration of drawing operations.

Display: Apple offered a choice of two displays, a 12' black and white unit, and a more expensive 13' high-resolution color display based on Sony's Trinitron technology. More than one display could be attached to the computer, and objects could be easily dragged from one screen to the next. Third-party displays quickly became available. The Los Angeles Times reviewer called the color 'spectacular.'^[13] The operating system user interface remained black and white even on color monitors with the exception of the Apple logo, which appeared in rainbow color.

Storage: A 5.25-inch 40 MB internal SCSI hard disk was optional, as was a second internal 800 kilobyte 3.5-inch floppy disk drive.

Expansion: Six NuBus slots were available for expansion (at least one of which had to be used for a graphics card, as the Mac II had no onboard graphics chipset and the OS didn't support headless booting). It is possible to connect as many as six displays to a Macintosh II by filling all of the NuBus slots with graphics cards. Another option for expansion included the Mac286, which included an Intel 80286 chip and could be used for MS-DOS compatibility.

The original ROMs in the Macintosh II contained a bug that prevented the system from recognizing more than one megabyte of memory address space on a Nubus card. Every Macintosh II manufactured until approximately November 1987 had this defect. This happened because Slot Manager was not 32-bit clean.^[14] Apple offered a well-publicized recall of the faulty ROMs and released a program to test whether a particular Macintosh II had the defect. As a result, it is rare to find a Macintosh II with the original ROMs.^{[citation needed]}

Accessories: The Macintosh II and Macintosh SE were the first Apple computers since the Apple I to be sold without a keyboard. Instead the customer was offered the choice of the new ADB Apple Keyboard or the Apple Extended Keyboard as a separate purchase. Dealers could bundle a third-party keyboard or attempt to upsell a customer to the more expensive (and higher-profit) Extended Keyboard.

Audio: The Macintosh II was the first Macintosh to have the Chimes of Death accompany the Sad Mac logo whenever a serious hardware error occurred.

The new extensions featured for the Macintosh II at the time were A/ROSE and Sound Manager.^{[citation needed]}

Models[edit]

The Macintosh II was offered in three configurations. All systems included a mouse and a single 800 KB 3.5-inch floppy disk drive; a 68551 PMMU was available as an option.^[15]

• Macintosh II CPU: 1 MB RAM.
• Macintosh II 1/40 CPU: 1 MB RAM, internal 40-megabyte SCSI HDD.
• Macintosh II 4/40 CPU: 4 MB RAM, internal 40-megabyte SCSI HDD.

Timeline of Macintosh II models

Defect Mac Os 11

References[edit]

1. ^Edwards, Benj (June 7, 2012). 'The Macintosh II celebrates its 25th anniversary'. Macworld.
2. ^Bartimo, Jim (February 25, 1985). 'Macintosh: Success And Disappointment'. InfoWorld. p. 30. Retrieved January 27, 2015.
3. ^'The Color Convergence'.
4. ^Webster, Bruce (December 1985). 'Microcomputer Color Graphics-Observations'. BYTE. p. 405. Retrieved October 28, 2013.
5. ^'Local Area Networks Newsletter'. Vol. 5 no. 4. April 1987. p. 1.Cite magazine requires |magazine= (help)
6. ^'Apple Begins Shipments Of Macintosh II Computer'. Wall Street Journal. May 8, 1987.
7. ^'Mac GUI :: Macintosh II and Macintosh SE announced'. macgui.com. Retrieved April 11, 2018.
8. ^Michael Wang (September 13, 1988). 'Apple price increases'. Newsgroup: comp.sys.mac. Usenet:3642@Portia.Stanford.EDU.
9. ^Apple Announces 68030 Macintosh IIx With High Density Compatible DriveArchived September 8, 2012, at archive.today by John Cook and Carol Cochrane, Business Wire 09/19/88 (retrieved September 20, 2009)
10. ^Series: The 24-bit ROM Blues by Adam C. Engst, Tidbits, April 22, 1991 (retrieved September 21, 2009)
11. ^'OLD-COMPUTERS.COM : The Museum'. www.old-computers.com. Retrieved April 11, 2018.
12. ^'Macintosh II High Resolution Video Card'. lowendmac.com. June 7, 1989. Retrieved April 11, 2018.
13. ^Magid, Lawrence J. (March 2, 1987). 'Apple's Two New Machines Are Dandy'. Los Angeles Times. Retrieved June 20, 2019. ..the color is spectacular. Unlike most color monitors, it also displays very readable text.
14. ^InfoWorld Magazine, October 26, 1987, p.47
15. ^'Macintosh II - Product Details'(PDF). Apple.

External links[edit]

• Mac II profile on Low End Mac
• Macintosh II technical specifications at apple.com