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Mac OS Nanokernel
The Mac OS nanokernel is an operating system Kernel (operating system), kernel serving as the basis of most PowerPC based system software versions 7 through 9 of the classic Mac OS, predating macOS, Mac OS X. The initial revision of this software is a single tasking system which delegates most tasks to an emulator running the Motorola 68000 series (68K) version of the operating system. The second major revision supports Computer multitasking, multitasking, multiprocessing, and message passing, and would be more properly called a microkernel. Unlike the 68K-derived Mac OS kernel running within it, the PowerPC kernel exists in a protected memory space and executes device drivers in user mode. The nanokernel is very different from the Copland OS microkernel, although they were created in succession with similar goals. System 7.1.2 – Mac OS 8.5.1 The original nanokernel, and the tightly integrated Mac 68k emulator, were written by emulator, emulation consultant Gary Davidian. Its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer from cellular phones and video game consoles to web servers and supercomputers. The dominant general-purpose personal computer operating system is Microsoft Windows with a market share of around 74.99%. macOS by Apple Inc. is in second place (14.84%), and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mac 68k Emulator
The Mac 68k emulator is a software emulator built into all versions of the classic Mac OS for PowerPC. This emulator enabled running applications and system code that were originally written for the 680x0-based Macintosh models. With a few exceptions, notably Connectix's RAM Doubler, the emulator ran all software with no noticeable impact other than lower performance relative to the same program when compiled for PowerPC. Origins The first version was written by Gary Davidian, who had originally created it for use on the Motorola 88000 CPU, used in Apple's abortive first attempt at a RISC target platform. A later version, using dynamic recompilation, was developed by Eric Traut, who later worked on successful emulation projects at Connectix such as Virtual Game Station and Virtual PC. Prior to Traut's arrival there, Connectix had released Speed Doubler, which included an even faster PowerPC 68k emulator. Implementation All versions of this emulator emulated the "user" subset of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiprocessing Services
In computing, Multiprocessing Services is a component of the Classic Mac OS and the retired Carbon API allowing programs to perform work across multiple preemptively scheduled threads of execution. Release history Multiprocessing Services was introduced in 1996 with the release of System 7.5.3. Multiprocessing Services 2.0, introduced in Mac OS 8.6, is a backwards-compatible major release that increases the level of integration preemptive tasks have with the rest of the system. Multiprocessing Services 2.1, introduced in Mac OS 9, adds support for devices with more than 1 GB of RAM. In the Classic Mac OS In the Classic Mac OS, Multiprocessing Services is not the only threading mechanism; cooperatively scheduled threads can be created with the Thread Manager. While applications using Multiprocessing Services have their threads preemptively scheduled, the application as a whole is still cooperatively scheduled with other running applications. Non-Multiprocessing Services tasks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macintosh Clone
A Macintosh clone, also known as a Clonintosh (a portmanteau of "Clone (computing), Clone" and "Macintosh"), is a computer running the Mac OS operating system that was not produced by Apple Inc. The earliest Mac clones were based on Macintosh clone#Emulators, emulators and reverse-engineered Macintosh Read-only memory, ROMs. During Apple's short lived Mac OS 7 licensing program, authorized Mac clone makers were able to either purchase 100% compatible motherboards or build their own hardware using licensed Mac reference designs. Since Apple's Mac transition to Intel processors, switch to the Intel platform, many non-Apple Wintel/Personal computer, PC computers are technologically so similar to Mac computers that they are able to boot the Mac OS, Mac operating system using a varying combination of community-developed patches and hacks. Such a Wintel/PC computer running macOS is more commonly referred to as a Macintosh clone#Hackintosh, Hackintosh. Background The Apple II series, Ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DayStar Digital
DayStar Digital, Inc. was a company founded in 1983 by Andrew Lewis as a subcontract manufacturer of electronic assemblies and circuit boards. In 1986, the company released memory upgrades for Apple Macintosh (Mac) computers as its first products, and in 1987, DayStar began to market processor upgrades exclusively for the Mac, the first being for the Apple Macintosh II computer. The company focused exclusively on this market for the full range of Mac computers through 1995, utilizing the Motorola 68030, 68040 and PowerPC 601 processors. These upgrades were installed directly into the Processor Direct Slot of various Macintosh platforms, as on the Macintosh IIci, or via an adapter. DayStar became known as the leading "speed shop" for Macintosh computer systems; it won virtually every Mac editorial award given for product excellence and had the top rated brand among peripheral manufacturers. The company also formed unique strategic relationships with many companies including Apple, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Transport
Open Transport was the name given by Apple Inc. to its implementation of the Unix-originated UNIX System V, System V STREAMS networking stack. Based on code licensed from Mentat's Mentat Portable Streams, Portable Streams product, Open Transport was built to provide the classic Mac OS with a modern TCP/IP implementation, replacing MacTCP. Apple also added its own implementation of AppleTalk to the stack to support legacy networks. History STREAMS Prior to the release of Open Transport, the classic Mac OS used a variety of stand-alone INIT (Mac OS), INITs to provide networking functionality. The only one that was widely used throughout the OS was the AppleTalk system. Among the other protocol stacks supported, MacTCP was becoming increasingly important as the Internet boom started to gain momentum. MacTCP emulated the Berkeley sockets system, widely used among Unix-like operating systems. MacTCP and the previous generation AppleTalk library were slow on PowerPC-based Macintoshes b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Protection
Memory protection is a way to control memory access rights on a computer, and is a part of most modern instruction set architectures and operating systems. The main purpose of memory protection is to prevent a process from accessing memory that has not been allocated to it. This prevents a bug or malware within a process from affecting other processes, or the operating system itself. Protection may encompass all accesses to a specified area of memory, write accesses, or attempts to execute the contents of the area. An attempt to access unauthorized memory results in a hardware fault, e.g., a segmentation fault, storage violation exception, generally causing abnormal termination of the offending process. Memory protection for computer security includes additional techniques such as address space layout randomization and executable space protection. Methods Segmentation Segmentation refers to dividing a computer's memory into segments. A reference to a memory location incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copland (operating System)
Copland is an operating system developed by Apple for Macintosh computers between 1994 and 1996 but never commercially released. It was intended to be released as ''System 8'', and later, ''Mac OS 8''. Planned as a modern successor to the aging System 7, Copland introduced protected memory, preemptive multitasking, and several new underlying operating system features, while retaining compatibility with existing Mac applications. Copland's tentatively planned successor, codenamed ''Gershwin'', was intended to add more advanced features such as application-level multithreading. Development officially began in March 1994. Over the next several years, previews of Copland garnered much press, introducing the Mac audience to basic concepts of modern operating system design such as object orientation, crash-proofing, and multitasking. In May 1996, Gil Amelio stated that Copland was the primary focus of the company, aiming for a late-year release. Internally, however, the development ef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peripheral Component Interconnect
Peripheral Component Interconnect (PCI) is a local computer bus for attaching hardware devices in a computer and is part of the PCI Local Bus standard. The PCI bus supports the functions found on a processor bus but in a standardized format that is independent of any given processor's native bus. Devices connected to the PCI bus appear to a bus master to be connected directly to its own bus and are assigned addresses in the processor's address space. It is a parallel bus, synchronous to a single bus clock. Attached devices can take either the form of an integrated circuit fitted onto the motherboard (called a ''planar device'' in the PCI specification) or an expansion card that fits into a slot. The PCI Local Bus was first implemented in IBM PC compatibles, where it displaced the combination of several slow Industry Standard Architecture (ISA) slots and one fast VESA Local Bus (VLB) slot as the bus configuration. It has subsequently been adopted for other computer types. Typic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New World ROM
New World ROM computers are Macintosh models that do not use a Macintosh Toolbox ROM on the logic board. Due to Mac OS X not requiring the availability of the Toolbox, this allowed ROM sizes to shrink dramatically (typically from to ), and facilitated the use of flash memory for system firmware instead of the now more expensive and less flexible Mask ROM that most previous Macs used. A facility for loading the Toolbox from the startup device was, however, made available, allowing the use of Mac OS 8 and Mac OS 9 on New World machines. The New World architecture was developed for the Macintosh Network Computer, an unrealized project that eventually contributed several key technologies to the first-generation iMac. All PowerPC Macs from the iMac, the iBook, the Blue and White Power Mac G3 and the Bronze Keyboard (Lombard) PowerBook G3 forward are New World ROM machines, while all previous models (including the Beige Power Mac G3 and all other beige and platinum Macs) are Old W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Old World ROM
Old World ROM computers are the Macintosh (Mac) models that use a Macintosh Toolbox read-only memory (ROM) chip, usually in a socket (but soldered to the motherboard in some models). All Macs prior to the iMac, the iBook, the Blue and White Power Mac G3 and the Bronze Keyboard (Lombard) PowerBook G3 use Old World ROM, while said models, as well as all subsequent models until the introduction of the Intel-based EFI Models, are New World ROM machines. In particular, the Beige Power Mac G3 and all other beige and platinum-colored Power Macs are Old World ROM machines. In common use, the "Old World" designation usually applies to the early generations of PCI-based "beige" Power Macs (and sometimes the first NuBus-equipped models), but not the older Motorola 68000-based Macs; however, the Toolbox runs the same way on all three types of machines. Details PCI Power Macs with an Old World ROM contain an Open Firmware implementation, and a copy of the Macintosh Toolbox as an Open Firmwar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Read-only Memory
Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing software that is rarely changed during the life of the system, also known as firmware. Software applications (like video games) for programmable devices can be distributed as plug-in cartridges containing ROM. Strictly speaking, ''read-only memory'' refers to memory that is hard-wired, such as diode matrix or a mask ROM integrated circuit (IC), which cannot be electronically changed after manufacture. Although discrete circuits can be altered in principle, through the addition of bodge wires and/or the removal or replacement of components, ICs cannot. Correction of errors, or updates to the software, require new devices to be manufactured and to replace the installed device. Floating-gate ROM semiconductor memory in the form of erasab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
