Misplaced Pages

#690309

47-423: Escape Velocity and EV Override were written for the classic Mac OS, and therefore run natively only on Mac OS 9 and earlier. However, the third game in the series, Escape Velocity Nova , supports plug-ins (released with Ambrosia's authorization) that simulate the first two titles using the new game's engine. Since EV Nova was made for both Mac OS X and Microsoft Windows , Override - through Nova plug-ins -

94-675: A coffin , held a mock funeral to announce that Apple had stopped the development of Mac OS 9. The final version of Mac OS 9 and the "classic" Mac OS was Mac OS 9.2.2, released in December 2001. In June 2005, Jobs announced that the Macintosh platform would be transitioning to Intel x86 microprocessors. Developer documentation of the Rosetta PowerPC emulation layer revealed that applications written for Mac OS 8 or 9 would not run on x86-based Macs. The Classic Environment remains in

141-630: A dual-boot configuration (with Mac OS X being selected as the default). The "Mirrored Drive Doors" Power Mac G4 was one of the last Mac models overall to officially boot into Mac OS 9 while the "Antimony" titanium PowerBook G4 was the last PowerBook model able to run Mac OS 9 natively. While these final models of the Macs and PowerBooks have G4 processors with faster clock speeds of up to 1.25 GHz and 1 GHz respectively on some models, they were able to boot into Mac OS 9 natively without any issues. The majority of G4 Macs released in 2003 onwards that have

188-418: A guard page may be used, either for error detection or to automatically grow data structures. On some systems, the page fault mechanism is also used for executable space protection such as W^X . A memory protection key (MPK) mechanism divides physical memory into blocks of a particular size (e.g., 4 KiB), each of which has an associated numerical value called a protection key. Each process also has

235-469: A 1 GHz or higher processor never had their "Mac OS ROM" boot files updated to allow those Macs to officially boot into Mac OS 9 natively outside of the Classic environment . All G5 Macs are unable to boot directly into Mac OS 9 at all because there was no support for PowerPC G5 processors on Mac OS 9 (Mac OS 9 only supports G3 and G4 processors as of Mac OS 9.2.2) and therefore can only run Mac OS 9 under

282-562: A computer's memory into segments. A reference to a memory location includes a value that identifies a segment and an offset within that segment. A segment descriptor may limit access rights, e.g., read only, only from certain rings . The x86 architecture has multiple segmentation features, which are helpful for using protected memory on this architecture. On the x86 architecture, the Global Descriptor Table and Local Descriptor Tables can be used to reference segments in

329-443: 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

376-440: A different address space for each process, which provides hard memory protection boundaries. It is impossible for an unprivileged application to access a page that has not been explicitly allocated to it, because every memory address either points to a page allocated to that application, or generates an interrupt called a page fault . Unallocated pages, and pages allocated to any other application, do not have any addresses from

423-421: A government's and their allies' ships, and pirating civilians will lower their legal rating. Also, affecting the legal status of one government will directly affect those of its allies and inversely affect its enemies. Having a high legal rating will give the player access to missions for that government (which, in turn, can unlock that government's ships and outfits). On the other hand, a low legal status will cause

470-416: A mock funeral for OS 9. Apple billed Mac OS 9 as including "50 new features" and heavily marketed its Sherlock 2 software, which introduced a "channels" feature for searching different online resources and introduced a QuickTime -like metallic appearance. Mac OS 9 also featured integrated support for Apple's suite of Internet services known as iTools (later re-branded as .Mac, then MobileMe , which

517-450: A protection domain. A new register contains the permissions associated with each of the protection domain. Load and store operations are checked against both the page table permissions and the protection key permissions associated with the protection domain of the virtual address, and only allowed if both permissions allow the access. The protection key permissions can be set from user space, allowing applications to directly restrict access to

SECTION 10

#1732801378691

564-558: A protection key value associated with it. On a memory access the hardware checks that the current process's protection key matches the value associated with the memory block being accessed; if not, an exception occurs. This mechanism was introduced in the System/360 architecture. It is available on today's System z mainframes and heavily used by System z operating systems and their subsystems. The System/360 protection keys described above are associated with physical addresses. This

611-467: A segmentation-like scheme and validating the target address and length of each instruction in real time before actually executing them. The simulator must calculate the target address and length and compare this against a list of valid address ranges that it holds concerning the thread's environment, such as any dynamic memory blocks acquired since the thread's inception, plus any valid shared static memory slots. The meaning of "valid" may change throughout

658-491: A single page table, a page table for each process, a page table for each segment, or a hierarchy of page tables, depending on the architecture and the OS. The page tables are usually invisible to the process. Page tables make it easier to allocate additional memory, as each new page can be allocated from anywhere in physical memory. On some systems a page table entry can also designate a page as read-only. Some operating systems set up

705-417: A software-managed cache of a larger list of keys associated with a process. PA-RISC has 15–18 bits of key; Itanium mandates at least 18. Keys are usually associated with protection domains , such as libraries, modules, etc. In the x86, the protection keys architecture allows tagging virtual addresses for user pages with any of 16 protection keys. All the pages tagged with the same protection key constitute

752-426: A suitable boundary of the computer's physical memory, or be flagged as being protected. Virtual memory makes it possible to have a linear virtual memory address space and to use it to access blocks fragmented over physical memory address space. Most computer architectures which support paging also use pages as the basis for memory protection. A page table maps virtual memory to physical memory. There may be

799-431: A type of virtual memory , allows in-memory data not currently in use to be moved to secondary storage and back in a way which is transparent to applications, to increase overall memory capacity. On some systems, a request for virtual storage may allocate a block of virtual addresses for which no page frames have been assigned, and the system will only assign and initialize page frames when page faults occur. On some systems

846-410: Is also playable on those platforms. The player controls a ship represented from a bird's-eye point of view in third person. Most of the game takes place within this view, where the player can interact with ships and stellar objects within the star system they are presently in. There are over a hundred star systems in the game, all connected to one another by a series of hyperlanes. The player can utilize

893-612: Is different from the protection key mechanism used by architectures such as the Hewlett-Packard / Intel IA-64 and Hewlett-Packard PA-RISC , which are associated with virtual addresses, and which allow multiple keys per process. In the Itanium and PA-RISC architectures, translations ( TLB entries) have keys (Itanium) or access ids (PA-RISC) associated with them. A running process has several protection key registers (16 for Itanium, 4 for PA-RISC ). A translation selected by

940-590: Is generally used for debugging and testing purposes to provide an extra fine level of granularity to otherwise generic storage violations and can indicate precisely which instruction is attempting to overwrite the particular section of storage which may have the same storage key as unprotected storage. Capability-based addressing is a method of memory protection that is unused in modern commercial computers. In this method, pointers are replaced by protected objects (called capabilities ) that can only be created using privileged instructions which may only be executed by

987-419: The Classic environment or other emulation software. In recent years, unofficial patches for Mac OS 9 and the "Mac OS ROM" have been made to allow unsupported G4 Macs to boot into Mac OS 9 natively; however this is not officially supported by Apple. Aside from Apple-branded hardware that can be maintained and operated, Mac OS 9 can be operated in other environments such as Windows and Unix . This includes

SECTION 20

#1732801378691

1034-619: The Classic environment were the 867 MHz—1.25 GHz "Mirrored Drive Doors" Power Mac G4 released in August 2002 (which was re-released in June 2003 due to a perceived demand for Mac OS 9 machines) and the 867 MHz—1 GHz "Antimony" titanium PowerBook G4 ("TiBook") released in November 2002. Both the "Mirrored Drive Doors" Power Mac G4 and the "Antimony" titanium PowerBook G4 came preinstalled with both Mac OS 9 and Mac OS X in

1081-410: The Macintosh version of the game, rating it four stars out of five, and stated that "The gameplay is similar to that in the first version, but the scope and design behind the new final frontier override any comparisons." Macworld ' s Michael Gowan praised Escape Velocity . Mac OS 9 Mac OS 9 is the ninth and final major release of Apple's classic Mac OS operating system , which

1128-521: The PowerPC version of 10.4 ; however, x86 versions of OS X and the PowerPC version of 10.5 do not support the Classic environment. Mac OS 9 can be emulated by using SheepShaver , a PowerPC emulator available on multiple operating systems. It can be run on any machine with a supported CPU platform, including Intel-based Macs . It initially required an actual PowerPC processor present in the machine it

1175-491: The aforementioned SheepShaver software mentioned above. Although it provides PowerPC processor support, especially on Intel-based Macs, it can only run up to Mac OS 9.0.4 because it does not emulate a memory management unit. QEMU is another piece of software that has PowerPC emulation and is able to run all versions of Mac OS 9 up to Mac OS 9.2.2. (Shipped with Macs) (Shipped with Macs) (Shipped with Macs) Updates to Mac OS 9 include 9.0.4, 9.1, 9.2.1, and 9.2.2. Mac OS 9.0.4

1222-406: The application data without OS intervention. Since the protection keys are associated with a virtual address, the protection domains are per address space, so processes running in different address spaces can each use all 16 domains. In Multics and systems derived from it, each segment has a protection ring for reading, writing and execution; an attempt by a process with a higher ring number than

1269-458: The application point of view. A page fault may not necessarily indicate an error. Page faults are not only used for memory protection. The operating system may manage the page table in such a way that a reference to a page that has been previously paged out to secondary storage causes a page fault. The operating system intercepts the page fault, loads the required memory page, and the application continues as if no fault had occurred. This scheme,

1316-498: The basis for some virtual machines , most notably Smalltalk and Java . Currently, the DARPA-funded CHERI project at University of Cambridge is working to create a modern capability machine that also supports legacy software. Dynamic tainting is a technique for protecting programs from illegal memory accesses. When memory is allocated, at runtime, this technique taints both the memory and the corresponding pointer using

1363-497: The computer's memory. Pointers to memory segments on x86 processors can also be stored in the processor's segment registers. Initially x86 processors had 4 segment registers, CS (code segment), SS (stack segment), DS (data segment) and ES (extra segment); later another two segment registers were added – FS and GS. In paging the memory address space or segment is divided into equal-sized blocks called pages . Using virtual memory hardware, each page can reside in any location at

1410-415: 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 . Segmentation refers to dividing

1457-403: The government to restrict access to their ports and even cause them to attack the player on sight. Like its predecessor, EV Override is fully open-ended and does not force the player to get involved in any of the game's plots, nor does it make a player continue a plot once they're in it. Players have the option to take the storylines and cause their actions to have a major impact on the galaxy. On

Escape Velocity Override - Misplaced Pages Continue

1504-533: The introduction of an automated Software Update engine and support for multiple users . Apple discontinued development of Mac OS 9 in late 2001, transitioning all future development to Mac OS X. The final updates to Mac OS 9 addressed compatibility issues with Mac OS X while running in the Classic Environment and compatibility with Carbon applications. At the 2002 Worldwide Developers Conference , Steve Jobs began his keynote address by staging

1551-492: The kernel, or some other process authorized to do so. This effectively lets the kernel control which processes may access which objects in memory, with no need to use separate address spaces or context switches . Only a few commercial products used capability based security: Plessey System 250 , IBM System/38 , Intel iAPX 432 architecture and KeyKOS . Capability approaches are widely used in research systems such as EROS and Combex DARPA browser. They are used conceptually as

1598-429: The lanes to perform a hyper-jump to a nearby system, which takes one to three days depending on their ship's mass. Players can land at planets, stations, and some other stellar objects. Here, if the location is inhabited, they can access a mission computer to take jobs, purchase new ships, trade commodities, refuel, customize their ship with various weapons and outfits, and go to a spaceport bar to hire escort ships, watch

1645-529: The machine, even though most Macs that can run the Classic environment are not necessarily able to boot into Mac OS 9 natively. Some Mac OS 9 applications do not run well in Classic; they demonstrate screen redraw problems and lagging performance. In addition, some drivers and other software which directly interact with the hardware fail to work properly. In May 2002, at Apple's Worldwide Developers Conference in San Jose, California , Steve Jobs , accompanied by

1692-514: The name Tagged Memory. The protection level of a particular implementation may be measured by how closely it adheres to the principle of minimum privilege . Different operating systems use different forms of memory protection or separation. Although memory protection was common on most mainframes and many minicomputer systems from the 1960s, true memory separation was not used in home computer operating systems until OS/2 (and in RISC OS )

1739-420: The news, gamble, and sometimes receive additional unique missions. Not all services are available at all locations. However, all inhabited locations have a mission computer and refueling option, and all stellar objects that can be landed on serve as a haven for the repair of the player's shields and armor. The star systems of Override are controlled by various governments, each with a different disposition towards

1786-573: The other hand, they can also simply become a commodity trader, cargo runner, or pirate and leave the galaxy to fend for itself. Players can purchase (or capture) and outfit many ships in the game as they see fit, allowing for many methods and styles for playing the game. Also, once they become powerful enough, players also have the option of forcing worlds to pay them daily tribute by destroying their defense fleets. This, however, may cause serious drops in their legal status elsewhere, and causes bounty hunters to start chasing them. Next Generation reviewed

1833-417: The player. Most start off as neutral with the player, though some may restrict access to their planets and stations and still others may be openly hostile and attack the player on sight. The player, however, can change their status with various governments. Taking missions for a government, attacking their enemies, and destroying pirates ("renegades") boosts status, whereas helping opposing governments, attacking

1880-505: The ring number for the segment causes a fault. There is a mechanism for safely calling procedures that run in a lower ring and returning to the higher ring. There are mechanisms for a routine running with a low ring number to access a parameter with the larger of its own ring and the caller's ring. Simulation is the use of a monitoring program to interpret the machine code instructions of some computer architectures. Such an instruction set simulator can provide memory protection by using

1927-546: The same taint mark. Taint marks are then suitably propagated while the program executes and are checked every time a memory address m is accessed through a pointer p ; if the taint marks associated with m and p differ, the execution is stopped and the illegal access is reported. SPARC M7 processors (and higher) implement dynamic tainting in hardware. Oracle markets this feature as Silicon Secured Memory (SSM) (previously branded as Application Data Integrity (ADI)). The lowRISC CPU design includes dynamic tainting under

Escape Velocity Override - Misplaced Pages Continue

1974-422: The thread's life depending upon context. It may sometimes be allowed to alter a static block of storage, and sometimes not, depending upon the current mode of execution, which may or may not depend on a storage key or supervisor state. It is generally not advisable to use this method of memory protection where adequate facilities exist on a CPU, as this takes valuable processing power from the computer. However, it

2021-404: The virtual address has its key compared to each of the protection key registers. If any of them match (plus other possible checks), the access is permitted. If none match, a fault or exception is generated. The software fault handler can, if desired, check the missing key against a larger list of keys maintained by software; thus, the protection key registers inside the processor may be treated as

2068-528: Was a collection of bug fixes primarily relating to USB and FireWire support. Mac OS 9.1 included integrated CD burning support in the Macintosh Finder and added a new Window menu in the Finder for switching between open windows. Mac OS 9.2 increased performance noticeably and improved Classic Environment support. Protected memory Memory protection is a way to control memory access rights on

2115-450: Was replaced by iCloud ) and included improved TCP/IP functionality with Open Transport 2.5. Other features new to Mac OS 9 include: PowerPC versions of Mac OS X prior to 10.5 include a compatibility layer called Classic , enabling users to run applications and hardware requiring Mac OS 9 from within OS X. This is achieved through running Mac OS 9 without access to its Finder inside OS X. This requires Mac OS 9 to be installed on

2162-641: Was running on similar to a hypervisor , but support for x86 platforms was added later. However, SheepShaver cannot run Mac OS versions newer than 9.0.4, as it does not have support for a memory management unit . The PearPC PowerPC emulator does not support Mac OS 9. QEMU has experimental support for running Mac OS 9 using PowerPC G4 emulation. As late as 2004, Mac OS 9 continued to be preinstalled on some Macs despite its development being stopped in late 2001, with most Macs made prior to 2003 having Mac OS 9 preinstalled alongside Mac OS X. The final Macs that were able to boot into Mac OS 9 natively without resorting to

2209-523: Was succeeded by Mac OS X 10.0 in 2001, starting the Mac OS X family of operating systems . Introduced on October 23, 1999, it was promoted by Apple as "The Best Internet Operating System Ever", highlighting Sherlock 2 ’s Internet search capabilities, integration with Apple's free online services known as iTools and improved Open Transport networking. While Mac OS 9 lacks protected memory and full pre-emptive multitasking , lasting improvements include

#690309