Showing all three icons of the OldWorld ROM (From Left to Right: Missing OS, Happy Mac (Found OS), and Sad Mac Logos

Old World ROM Macintosh computers are the Macintosh models that use a Macintosh Toolbox ROM chip, usually in a socket (but soldered to the motherboard in some models). Macintosh, commonly nicknamed Mac is a Brand name which covers several lines of Personal computers designed developed and marketed by Apple Inc The Macintosh Toolbox is a set of Application programming interfaces with a particular access mechanism All Macs prior to the iMac use Old World ROM, while the iMac and all subsequent models are New World ROM machines. The iMac is a desktop Macintosh computer designed and built by Apple Inc New World ROM Macintosh computers are the PowerPC Macintosh models that do not use a Macintosh Toolbox ROM on the motherboard but instead In common use, the "Old World" designation usually applies to the early generations of PCI-based "beige" Power Macs (and sometimes the very 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. The Peripheral Component Interconnect, or PCI Standard (commonly PCI) specifies a Computer bus for attaching peripheral devices to a Computer Power Macintosh, later Power Mac, is a line of Apple Macintosh Workstation -class Personal computers based on various models of PowerPC NuBus is a 32-bit parallel Computer bus, originally developed at MIT as a part of the NuMachine Workstation The Motorola 68000 is a 16/32-bit CISC Microprocessor core designed and marketed by Freescale Semiconductor (formerly Motorola Semiconductor

PCI Power Macs with an Old World ROM contain an Open Firmware implementation, and a copy of the Macintosh Toolbox as an Open Firmware device. Open Firmware, or OpenBoot in Sun Microsystems parlance is a standard defining the interfaces of a computer Firmware system formerly endorsed by the These machines are set to boot from this device by default, thus starting the normal Macintosh startup procedure. This can be changed, just as on New World ROM Macs, but with limitations placed on what devices and formats can be used; on these machines, particularly the early machines like the Power Macintosh 9500, the Open Firmware implementation was just enough to enumerate PCI devices and load the Toolbox ROM, and these Open Firmware revisions have several bugs which must be worked around by boot loaders or nvramrc patches. The Power Macintosh 9500 (the 132 MHz model is also known as Power Macintosh 9515 in Europe and Japan) is a high-end Macintosh Personal

All Power Macs include an emulated 68LC040 core that runs inside a nanokernel; this nanokernel/emulator combination is then used to boot the (predominantly 68k-based) Toolbox, and is also used to support applications written for the 68k once Mac OS is running. The Mac 68K emulator was a Software Emulator built into all versions of the Mac OS for PowerPC. 68k machines can boot into the Toolbox directly.

On all Old World ROM machines, once the Toolbox is loaded, the boot procedure is the same. The Toolbox does a memory test, enumerates Mac OS devices it knows about (this varies from model to model), and either starts the onboard video (if present) or the option ROM on a NuBus or PCI video card. The Toolbox then checks for a disk in the floppy drive, and scans all SCSI buses for a disk with a valid System Folder, giving preference to whatever disk is set as the startup disk in the parameter RAM. Non-volatile Random access memory ( NVRAM) is the general name used to describe any type of random access memory which does not lose its information

If a bootable disk is found, the Happy Mac logo is displayed, and control is handed over to Mac OS. A Happy Mac is the normal bootup (startup icon of an Apple Macintosh computer running older versions of the Mac OS Operating system. If no disk to boot from is present, an icon depicting a floppy disk with a question mark in the middle blinks on the screen. An icon (from Greek εἰκών eikōn, "image" is a religious work of art most commonly a painting from Eastern Christianity. If a hardware problem occurs during the early part of the boot process, the machine will play the Chimes of Death and freeze; on some Macs, this will be accompanied by a Sad Mac icon and an error code describing the problem. The Chimes of Death, also known as Hawaiian Death Chimes, are the Macintosh equivalent of an IBM PC POST error beep.

Since the Old World ROM usually boots to the Toolbox, most OSes have to be installed using a boot loader from inside Mac OS (BootX is commonly used for Linux installations). In Computing, booting ( booting up) is a bootstrapping process that starts Operating systems when the user turns on a Computer system 68K-based Macs and NuBus Power Macs must have Mac OS installed to load another OS (even A/UX, which was an Apple product), usually with virtual memory turned off. A/UX (from A pple U ni' x') was Apple Computer 's implementation of the Unix Operating system for some of their Macintosh Virtual memory is a Computer system technique which gives an application program the impression that it has contiguous working memory while in fact it may be physically PCI Power Macs can be configured to boot into Open Firmware, allowing the firmware to load a boot loader directly, or they can use a specially-prepared floppy disk to trick the Toolbox into loading a kernel (this is used for Linux installation floppy images). Linux (commonly pronounced ˈlɪnəks

The most simple way to distinguish an OldWorld ROM Mac is that it will not have a factory built-in USB port. Only NewWorld ROM Macs had a USB port as factory equipment.

See also

• BootX, the standard LinuxPPC boot loader for Old World machines
• Quik (boot loader), a replacement boot loader for Old World PCI systems

External links

• Macintosh: ROM Size for Various Models