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32-499: Models are listed in approximately chronological order. (Max. RAM sizes may be greater when third-party memory boards are used.) The Sun Type 3 keyboard is split into three blocks: It shipped with Sun-3 systems. In 1989, coincident with the launch of the SPARCstation 1 , Sun launched three new Sun-3 models, the 3/80, 3/470 and 3/480. Unlike previous Sun-3s, these use a Motorola 68030 processor, 68882 floating-point unit, and

64-610: A micromechanical resonator on the silicon chip of the RTC. This reduces the size and cost of an RTC by reducing its parts count. Micromechanical resonators are much more sensitive to temperature than quartz resonators. So, these compensate for temperature changes using an electronic thermometer and electronic logic. Typical crystal RTC accuracy specifications are from ±100 to ±20 parts per million (8.6 to 1.7 seconds per day), but temperature-compensated RTC ICs are available accurate to less than 5 parts per million. In practical terms, this

96-438: A thermistor and analog-to-digital converter ) and uses a polynomial to calculate "rate" about once per minute. These require a calibration that measures the frequency at several temperatures, and then a linear regression to find the equation of temperature. The most common quartz crystals in a system are SC-cut crystals, and their rates over temperature can be characterized with a 3rd-degree polynomial. So, to calibrate these,

128-570: A 50-pin cable. The SPARCstation 1 comes with an on-board AMD Lance Ethernet chipset and a 15-pin AUI connector, which can connect to 10BASE2, 10BASE5 or 10BASE-T via an appropriate transceiver. The OpenBoot ROM is able to boot from network, using RARP and TFTP. Like all other SPARCstation systems, the SPARCstation 1 holds system information such as MAC address and host id (serial number) in NVRAM. If

160-518: A new SCSI controller. The SPARCstation IPC (Sun 4/40) is a version of the SPARCstation 1+ in a lunchbox style case and onboard video. The SPARCstation SLC (Sun 4/20) is a version of the SPARCstation 1+ built into a monitor cabinet, announced in May 1990. The SPARCstation 2 (Sun 4/75) is the machine's successor and was released in November 1990. Real-time clock A real-time clock ( RTC )

192-474: A second) is subtracted from "time", and the clock's timing-chain software is invoked to count fractions of seconds, seconds, etc. With 32- bit variables for time and rate, the mathematical resolution of "rate" can exceed one part per billion. The clock remains accurate because it will occasionally skip a fraction of a second, or increment by two fractions. The tiny skip (" jitter ") is imperceptible for almost all real uses of an RTC. The complexity with this system

224-472: A substantial number of these systems now refuse to boot. Additionally, the SPARCstation 1 design used the reserved bits in the M48T02's NVRAM in a non-standard way; since later revisions of the M48T02 chip exert stricter control over these bits, a current M48T02 will store the NVRAM data, but the RTC will not function correctly and the system may fail to auto-boot. Due to incompatibilities with modern M48T02s, it

256-774: Is an electronic device (most often in the form of an integrated circuit ) that measures the passage of time. Although the term often refers to the devices in personal computers , servers and embedded systems , RTCs are present in almost any electronic device which needs to keep accurate time of day . The term real-time clock is used to avoid confusion with ordinary hardware clocks which are only signals that govern digital electronics , and do not count time in human units. RTC should not be confused with real-time computing , which shares its three-letter acronym but does not directly relate to time of day. Although keeping time can be done without an RTC, using one has benefits: A GPS receiver can shorten its startup time by comparing

288-471: Is common to modify failed NVRAMs by cutting into the encapsulation and patching in a new battery. It is also possible to replace the entire encapsulation, which also contains a 32.768 kHz clock crystal. The SPARCstation 1, 1+, IPC and SLC can run the following operating systems: The SPARCstation 1+ (Sun 4/65) pushed the CPU to a 25 MHz LSI L64801, upgraded the coprocessor to a Weitek 3172 and installed

320-437: Is converting dates and times to counts of seconds, but methods are well known. If the RTC runs when a unit is off, usually the RTC will run at two rates, one when the unit is on and another when off. This is because the temperature and power-supply voltage in each state is consistent. To adjust for these states, the software calculates two rates. First, software records the RTC time, reference time, on seconds and off seconds for

352-521: Is determining the instantaneous corrected value for the variable "rate". The simplest system tracks RTC time and reference time between two settings of the clock, and divides reference time by RTC time to find "rate". Internet time is often accurate to less than 20 milliseconds, so 8000 or more seconds (2.2 or more hours) of separation between settings can usually divide the forty milliseconds (or less) of error to less than 5 parts per million to get chronometer-like accuracy. The main complexity with this system

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384-496: Is good enough to perform celestial navigation , the classic task of a chronometer . In 2011, chip-scale atomic clocks became available. Although vastly more expensive and power-hungry (120 mW vs. <1 μW), they keep time within 50 parts per trillion ( 5 × 10 ). Many integrated circuit manufacturers make RTCs, including Epson , Intersil , IDT , Maxim , NXP Semiconductors , Texas Instruments , STMicroelectronics and Ricoh . A common RTC used in single-board computers

416-534: Is the Maxim Integrated DS1307. The RTC was introduced to PC compatibles by the IBM PC/AT in 1984, which used a Motorola MC146818 RTC. Later, Dallas Semiconductor made compatible RTCs, which were often used in older personal computers , and are easily found on motherboards because of their distinctive black battery cap and silkscreened logo. A standard CMOS interface is available for

448-419: Is usually 32.768 kHz, the same frequency used in quartz clocks and watches . Being exactly 2 cycles per second, it is a convenient rate to use with simple binary counter circuits. The low frequency saves power, while remaining above human hearing range . The quartz tuning fork of these crystals does not change size much from temperature, so temperature does not change its frequency much. Some RTCs use

480-430: Is yet very repeatable (often less than 1 ppm). Software can do the math to make these into accurate RTCs. The hardware timer can produce a periodic interrupt, e.g. 50  Hz , to mimic a historic RTC (see below). However, it uses math to adjust the timing chain for accuracy: time = time + rate. When the "time" variable exceeds a constant, usually a power of two, the nominal, calculated clock time (say, for 1/50 of

512-484: The NeXT Computer , and Sun's own 3/80 . It sold for between about US$ 9,000 (equivalent to $ 22,100 in 2023) with no hard disks, to US$ 20,000 — and in the first year around 35,000 units were sold. The SPARCstation 1 features several distinctive design and packaging elements driven internally by system designer Andy Bechtolsheim and externally by design house frog design . Bechtolsheim specified that

544-527: The sun4c architecture. The motherboard has three SBus slots, built-in AUI Ethernet , 8 kHz audio, and a 5 MB/s SCSI-1 bus. The basic display runs at 1152 × 900 in 256 colours, and monitors shipped with the computer were 16 to 19 inch greyscale or colour. Designed for ease of production to compete with high-end PCs or Macs , its principal competitors were the IBM PS/2 Model 80 ,

576-411: The 68030's integral MMU. This 68030-based architecture is called Sun-3x . Sun 3/260s upgraded with Sun 3400 CPU boards are known as Sun 3/460 s. SPARCstation 1 The SPARCstation 1 (Sun 4/60, code-named Campus ) is the first of the SPARCstation series of SPARC -based computer workstations sold by Sun Microsystems . The design originated in 1987 by a Sun spin-off company, UniSun, which

608-567: The IBM 360, the interrupt updates a 64-bit count of microseconds utilized by standardized systems software. The clock's jitter error is half if the clock interrupts for each zero crossing, instead of each cycle. The clock also usually formed the basis of computers' software timing chains; e.g. it was usually the timer used to switch tasks in an operating system. Counting timers used in modern computers provide similar features at lower precision, and may trace their requirements to this type of clock. (e.g. in

640-625: The OpenBoot firmware will not boot from any partition which starts or ends after 1024 MB. The floppy drive, like the Macintosh's, is unusual in that it has an electromechanical eject mechanism rather than the conventional eject button, and therefore must be ejected by the operating system or OpenBoot. The machine can connect to any SCSI CD drive, via either the SCSI connector on the back or by connecting it to any spare internal SCSI connector via

672-465: The PC RTC. In newer computer systems, the RTC is integrated into the southbridge chip. Some microcontrollers have a real-time clock built in, generally only the ones with many other features and peripherals . Some modern computers receive clock information by digital radio and use it to promote time-standards. There are two common methods: Most cell phone protocols (e.g. LTE ) directly provide

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704-662: The actual methods of efficient high-speed manufacturing are proprietary. Some computer designs such as smaller IBM System/360s , PDP-8s and Novas used a real-time clock that was accurate, simple and low cost. In Europe, North America and some other grids, the frequency of the AC mains is adjusted to the long-term frequency accuracy of the national standards. In those grids, clocks using AC mains can keep perfect time without adjustment. Such clocks are not practical in portable computers or grids (e.g. in South Asia) that do not regulate

736-413: The battery on this chip dies, then the system will not be able to boot. The SPARCstation 1 uses an M48T02 battery-backed RTC with RAM chip which handles the real time clock and boot parameter storage. A problem with this chip is that the battery is internal, which means the entire chip must be replaced when its battery runs out. As all SPARCstation 1s made are now older than the battery life of this chip,

768-613: The current local time. If an internet radio is available, a computer may use the network time protocol . Computers used as local time servers occasionally use GPS or ultra-low frequency radio transmissions broadcast by a national standards organization (i.e. a radio clock ). The following system is well-known to embedded systems programmers, who sometimes must construct RTCs in systems that lack them. Most computers have one or more hardware timers that use timing signals from quartz crystals or ceramic resonators . These have inaccurate absolute timing (more than 100 parts per million) that

800-406: The current time, according to its RTC, with the time at which it last had a valid signal. If it has been less than a few hours, then the previous ephemeris is still usable. Some motherboards are made without RTCs. The RTC may be omitted out of desire to save money or reduce possible sources of hardware failure. RTCs often have an alternate source of power, so they can continue to keep time while

832-460: The frequency is measured at four temperatures. The common tuning-fork-style crystals used in watches and many RTC components have parabolic (2nd-degree) equations of temperature, and can be calibrated with only 3 measurements. MEMS oscillators vary, from 3rd degree to fifth degree polynomials, depending on their mechanical design, and so need from four to six calibration measurements. Something like this approach might be used in commercial RTC ICs, but

864-501: The frequency of AC mains. These computers' power supplies use a transformer or resistor divider to produce a sine wave at logic voltages. This signal is conditioned by a zero crossing detector, either using a linear amplifier , or a schmitt trigger . The result is a square wave with single, fast edges at the mains frequency. This logic signal triggers an interrupt. The interrupt handler software usually counts cycles, seconds, etc. In this way, it can provide an entire clock and calendar. In

896-539: The motherboard would be the size of a sheet of paper and the SBus expansion cards would be the size of index cards, resulting in an extremely compact footprint. The external design motif includes dot-patterned cooling vents on the side which are echoed by a "dimple" pattern on the front face, and "Sun purple" feet. The SPARCstation 1 takes 30-pin SIMMs in groups of four. It can take either 1 MB or 4 MB SIMMs as long as

928-435: The primary source of power is off or unavailable. This alternate source of power is normally a lithium battery in older systems, but some newer systems use a supercapacitor , because they are rechargeable and can be soldered . The alternate power source can also supply power to battery backed RAM . Most RTCs use a crystal oscillator , but some have the option of using the power line frequency . The crystal frequency

960-479: The size is consistent within a bank. There are a total of four memory banks, which can give a total of 64 MB of memory. Memory bank 0 (composed of U0311, U0322, U0309, and U0307) should be filled first. If not, the OpenBoot firmware will hang while memory checking. The SPARCstation 1 has space for up to two hard drives and one floppy drive internally. The machine will take any 50-pin SCSI -2 hard drive, but

992-407: The two intervals between the last three times that the clock is set. Using this, it can measure the accuracy of the two intervals, with each interval having a different distribution of on and off seconds. The rate math solves two linear equations to calculate two rates, one for on and the other for off. Another approach measures the temperature of the oscillator with an electronic thermometer, (e.g.

Sun-3 - Misplaced Pages Continue

1024-512: Was soon re-acquired. The SPARCstation 1 has a distinctive slim enclosure (a square 3-inch-high " pizza box ") and was first sold in April 1989, with Sun's support ending in 1995. Based on an LSI Logic RISC CPU running at 20 MHz, with a Weitek 3170 (or 3172) FPU coprocessor , it was the fourth Sun computer (after the 4/260, 4/110 and 4/280) to use the SPARC architecture and the first of

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