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This program (written in Visual Basic) let my Z80 NANO COMPUTER communicate with an IBM PC Computer. You can choose either a serial or a parallel transmission for both the directions.
This 60 sec. video demo will show both Serial and Parallel transmission (TX and RX respectively)
In the demo the software will import the Assembly code from a third-party PC Z80 Simulator and then transmit it from the PC to the Z80 NANO COMPUTER ram. This trasmission in this demo is serial (RS-232). A 16 bit checksum is calculated on both the machines, transmitted to the Z80 machine and there checked. Serial transmission allows also a parity checking control. Then the program will re-import data from the Z80 to the PC, via parallel transmission this time. I have choosed a slow 10 ms handshaking to let you see the data while imported. A 16 bit checksum is calculated on both the machines, transmitted from the Z80 to the PC and here checked.
Hexadecimal data are manually copied from the program and pasted in a notepad to show you that data have been sent and received in a correct way.
The seven trimmers (all connected to a 555 oscillating circuit) are tuned to play the seven musical notes (Major Scale). The two quad analog/bilateral switch 4016 select the appropriate resistor, according to a seven bits word. The last bit is used to activate or mute the sound. The amplifier is just a simple general purpose low-power amplifying transistor (2N2222A).
◦ Co-processor manufacturer: AMD (AM9511) or Rochester Electronics replacement, licensed by Intel (c) 1980 (C8231A).
Rochester Electronics is licensed and authorized by semiconductor manufacturers to provide a continuing manufacturing source for mature/discontinued products.
AM9511 APU performs floating point calculations that would be too time-consuming or cumbersome if done on Z80. In addition to the four basic operations, the 9511 can implement transcendental functions (sin, log, etc.), and it can also perform conversion from floating point to fixed point and vice versa. It can also perform operations in 16 or 32 bit fixed point two's complement integer representation.
I ran into Mr. Oshman and his Wife at an event I covered this afternoon. I post this more for posterity than any other reason.
Mr. Oshman is one of the four founders of ROLM. He was the President & CEO of the company and is the "O" in the company name. The remaining letters coming from the other three founders; Gene Richeson (R), Walter Lowenstern (L) and Robert Maxfield (M).
I worked for ROLM from 1979 to 1989, then again from 1992 to 1994. I held various positions during my years of employment there. I was a cable puller, an installation technician, a software development engineer and eventually held several management positions in software engineering and product support.
ROLM was my first "real" job, as I started with them late in my 19th year. I'm forever thankful for my time with the company as they provided me, a high school dropout with a 9th grade education, the opportunity to explore the things which most interested me, which at the time (and still is) computer systems operations.
The company was a pioneer in the development of all-digital voice systems, which included CBX's (Computerized Branch Exchanges) and digital phones. They also pioneered the first commercial voice messaging systems, now known as voice mail.
I learned how computers worked, and subsequently how to program them, using a ROLM Data General 1603 hard panel. (The 1603 processor was based on the Data General Nova minicomputer. In the company's early days, they used these systems to develop mil-spec computer applications, such as terrain guidance systems for cruise missiles and weather instrumentation for F-16 fighter jets.)
Earlier this decade I worked as a consultant for another company founded by Mr. Oshman; Echelon Corporation, of which he is currently Chairman & CEO.
I am forever thankful for the opportunities afforded me by ROLM and will always hold Mr. Oshman in the absolute highest regard for the way he managed what was truly a great Silicon Valley company.
The mills are an important feature of Maynard's development. The earliest saw and grist mills were built in the early 18th century. Two of the earliest mills were the Puffer Mill and the Asa Smith's Mill, which were located on Taylor Brook and Mill Street, respectively. These were the first mills to use the Assabet River for power; therefore, they were very slow and sluggish. The grist and saw mill were then followed by paper mills, which were built starting in 1820.
The Mill is easily Maynard's most prominent feature. The complex takes up 11 acres in the middleof what we call downtown. The Mill complex began in 1847 as set of wooden buildings used to manufacture carpets and carpet yarn. Amory Maynard helped construct this mill. His partner, William H. Knight, helped him build a dam across the Assabet and dug a canal channeling a portion of the river into what is called Mill Pond. The Mill changed hands a few times but it would eventually become the largest woolen factory in the world till the 1930s.
The 1950's ushered in a change from textiles to businesses like computer manufacturing. With the start of the final decade of the century the Mill is on the cusp of being transformed again.
It is said that "as the Mill goes, so goes Maynard". While the town isn't as dependent on the Mill as it was in 19th century it continues to play an important role in shaping the character of the town.
We hope you enjoy this historical perspective of the Mill. It has been pieced together from a variety of sources and continues to be enriched as we discover new materials to include, increase the number of hyperlinks and add pictures, diagrams, and sound..
The Mill from 1847 to 1977
The site of the mill was once part of the town of Sudbury, while the opposite bank of the Assabet River belonged to Stow. The present town, formed in 1871, was named for the man most responsible for its development, Amory Maynard.
Born in 1804, Maynard was running his own sawmill business at the age of sixteen. In the 1840's, he went into partnership with a carpet manufacturer for whom he'd done contracting. They dammed up the Assabet and diverted water into a millpond to provide power for a new mill, which opened in 1847, producing carpet yarn and carpets. Only one of the original mill buildings survives: it was moved across Main Street and now is an apartment house.
Amory Maynard's carpet firm failed in the business panic of 1857. But the Civil War allowed the Assabet Manufacturing Company, organized in 1862 with Maynard as the managing "agent", to prosper by producing woolens, flannels and blankets for the army. This work was carried on in new brick mill buildings.
Expansion of the mill over many years is evidenced by the variations in the architecture of the structures still standing.
The oldest portion of Building 3 dates from 1859, making it the oldest part of the mill in existence today, but several additions were made afterwards. Buildings constructed in the late 1800's frequently featured brick arches over the windows, and at times new additions were made to match neighboring structures.
The best-known feature is the clock donated in memory of Amory Maynard by his son Lorenzo in 1892. Its four faces, each nine feet in diameter, are mechanically controlled by a small timer inside the tower. Neither the timer nor the bell mechanism has ever been electrified; custodians still climb 120 steps to wind the clock every week- 90 turns for the timer and 330 turns for the striker.
Amory Maynard died in 1890, but his son and grandson still held high positions in the mill's management. The family's local popularity plummeted, however, when the Assabet Manufacturing Company failed late in 1898. Workers lost nearly half of their savings which they had deposited with the company, since there were no banks in town. Their disillusionment nearly resulted in changing the town's name from Maynard to Assabet.
Prosperity returned in 1899 when the American Woolen Company, an industrial giant, bought the Assabet Mills and began to expand them, adding most of the structures now standing. The biggest new unit was Building 5, 610 feet long which contained more looms than any other woolen mill in the world. Building 1, completed in 1918, is the newest; the mill pond had been drained to permit construction of its foundation. These buildings have little decoration, but their massiveness is emphasized by the buttress-like brick columns between their windows.
The turn of the century saw a changeover from gas to electric lights at the mill. Until the 1930's the mill generated not only its own power but also electricity for Maynard and several other towns. For years the mill used 40-cycle current. Into the late 1960's power produced by a water wheel was used for outdoor lighting, including the Christmas tree near Main Street. The complex system of shafts and belts once used to distribute power from a central source was rendered obsolete by more efficient small electric motors, just as inexpensive minicomputers have often replaced terminals tied to one large processor.
As the mill grew, so did the town. Even in 1871, the nearly 2,000 people who became Maynard's first citizens outnumbered the people left in either Sudbury or Stow. Maynard's first population almost doubled in the decade between 1895 and 1905, when reached nearly 7,000 people. Most of the workers lived in houses owned by the company, many of which have been refurbished and are used today. The trains that served th town and the mill, however, are long gone - the depot site is now occupied by a gas station.
Most of the original mill workers had been local Yankees and Irish immigrants. But by the early 1900's, the Assabet Mills were employing large numbers of newcomers from Finland, Poland, Russia and Italy. The latest arrivals were often escorted to their relatives or friends by obliging post office workers. The immigrants made Maynard a bustling, multi-ethnic community while Stow, Sudbury and Acton remained small, rural villages. Farmers and their families rode the trolley to Maynard to shop and to visit urban attractions then unknown in their own towns, including barrooms and movie houses.
Wages were low and the hours were long. Early payrolls show wages of four cents an hour for a sixty hour week. Ralph Sheridan of the Maynard Historical Society confirmed that in 1889 his eldest brother was making 5 1/2 cents an hour in the mill's rag shop at the age of fourteen, while their father was earning 16 1/2 cents per hour in the boiler room. (As of 1891 one-eighth of the workers were less than 16 years old, and one-quarter were women.)
Sheridan's own first job at the mill, in the summer of 1915, paid $6.35 for a work week limited to 48 hours by child labor laws. The indestructible "bullseye" safe still remains in the old Office Building.
Sheridan remembers the bell that was perched on top of Building 3:
"...the whistle on the engine room gave one blast at quarter of the hour, and then at about five minutes of the hour the gave one blast again. And everyone was supposed to be inside the gate when that second whistle blew. And then at one minute of the hour this bell rang just once, a quick ring- and we referred to it as "The Tick" because of that..... everybody was supposed to start work at that time, at that moment."
A worker was sent home if he'd forgotten to wear his employee's button, marked "A.W.Co.,Assabet".
The millhands really had to work, too. Sheridan recalls one winter evening when there was such a rush to get out an order of cloth for Henry Ford that the men were ordered to invoice it from the warehouse, now Building 21, instead of from the usual shipping room:
"There was no heat in the building, never had been. And it was so cold that I remember that I had to cut the forefinger and the thumb from the glove that I was wearing in order to handle the pencil to do the invoicing....the yard superintendant at the time brought in some kerosene lanterns and put 'em under our chairs to keep our feet warm."
Building 21, built out over the pond, remained unheated until DIGITAL took it over.
As in most Northern mill towns, labor relations were often troubled. In 1911 the company used Poles to break the strike of Finnish workers. When no longer able to play off one nationality against another, management for years took advantage of rivalries between different unions. The Great Depression hit the company hard, however. In 1934 it sold all the houses it owned, mostly to the employees who lived in them; and New Deal labor laws encouraged the workers to form a single industrial union, which joined the C.I.O.
World War II brought a final few years of good times to the woolens industry. The mill in Maynard operated around the clock with over two thousand employees producing such items as blankets and cloth for overcoats for the armed forces. But when peace returned, the long-term trends resumed their downward drift, and in 1950 the American Woolen Company shut down its Assabet Mills entirely. Like many New England mills, Maynard's had succumbed to a combination of Southern and foreign competition, relatively high costs and low productivity, and the growing use of synthetic fibers.
'Til then a one-industry town, Maynard was in trouble. In 1953, however, ten Worcester businessmen bought the mill and began leasing space to tenants, some of which were established firms, while others were just getting started. One of the new companies which found the low cost of Maynard Industries' space appealing was Digital Equipment Corporation, which started operations in 8,680 square feet in the mill in 1957.
A Mill Chronology
1846 Amory Maynard and William Knight form Assabet Mills.
1847 Maynard and Knight install a water wheel and build a new factory on the banks of the Assabet River.
1848 The Assabet Mills business is valued at $150,000.
The Lowell and Framingham Railroad carries passengers over branch road.
1855 The Mill now has three buildings on the site. Massachusetts is producing one-third of the textiles in the United States.
1857 Assabet Mills collapses after a business panic. The Mill complex is sold at an auction.
1862 The Mills are reorganized as Assabet Manufacturing Company. This involve replacing wooden buildings with brick, and the installation of new machinery. To fulfill contracts to the government during the Civil War production is switched from carpets to woolen cloth, blankets, and flannel.
The first tenement for employees are also constructed.
1869 Millhands peition President Ulysses S. Grant for a shorter work week ... 55 hours.
1871 The Town of Maynard incorporates. The population stands at 2,000
1888 A reservoir is installed for $70,000 to supply a growing population.
1890 The Assabet Manufacturing Company is valued at $1,500,000.
1892 Lorenzo Maynard donates clock in his father's name.
The Mill Complex contains seven buildings.
1898 Assabet Manufacturing Company declares bankruptcy. Many people in town lose much of their savings as banks have not yet been established.
1899 American Woolen Company purchases the Mill complex for $400,000. This company would eventually control 20% of the woolen textile market in the U.S. Wool was shipped all over the country to keep up with demand.
1901 160 additional tenements are constructed with their own sewage system. The streets are named after U.S. presidents.
The first electric trolley in Maynard begins service.
Building Number 5, the Mill complex's largest, is built in nine months. Electric power is introduced with the addition of dynamos on site.
1906 The Mill complex now has 13 buildings.
1910 The Mill complex grows to 25 buildings. Floor space is at 421,711 square feet. The property takes up 75 acres.
1918 With the addition of three new buildings the American Wollen Company and the Mill are in their heyday. The fortunes of the industry begin to decline over the next 30 years.
1947 After a brief spell of prosperity during World War II, the Mill phases out production as demand for woolen goods declines.
1950 Mill closes. 1,200 employees lose their jobs.
1953 Maynard Industries, Inc. purchases the Mill for $200,000. Space is rented to business and industrial tenants.
1957 Three engineers set up shop on the second floor of Building 12. With $70,000 and 8,600 square feet of rented space Digital Equipment Corporation is formed.
1960 Over thirty firms are located within the Mill complex.
1974 Digital Equipment Corporation purchases the entire Mill complex for $2.2 million. The Mill has over 1 million square feet in 19 buildings residing on 11 acres.
1992 The 100th anniversary of the Mill Clock is celebrated.
1993 Digital Equipment Corporation announces that it plans to leave the Mill complex. A search for a new tenant is started.
1995 Franklin Life Care purchases the Mill. Digital continues to rent space in Building 5.
1998 Mill purchased by Clock Tower Place.
Sources
* "Digital's Mill 1847-1977", a brochure published by Digital Equipment Corporation in 1977.
* "A Walk Through the Mill...", published by Digital Equipment Corporation for the Mill Clock Centennial.
MAXIM MAX232: THIS IS NOT a vintage component...sorry but I had only one single power supply rail (+5v) available...
For the delectation of Raspberry Pi users - This image may be freely used for non commercial purposes :-) see the creative commons licence.
So here's my daily dose of geekness. I got a new phone. Well actually it is a new minicomputer that can also telephone. Can you believe that this thing has a dual core 1.2 GHz processor. Probably the same power that desktop computers had 8 years ago...
Anyhow I am very glad that I could grab one. They are still rare.
One of the latest additions to the Hack42 Museum (Computermuseum Arnhem): a DEC PDP-8/f minicomputer.
The machine was graciously donated by our friends at Wageningen University.
The machine has a few stickers mainly directed at operators and service engineers, persons who to notify in case of problems and procedures to be carried out, as well as troubleshooting hints.
Compare this shot to one with a less shallow depth of field.
Low Cost (<20$) UV Eprom Eraser
Lamp: SANKYO DENKI GERMICIDAL LAMP: G6T5 6W
Erase Time (Minutes) : 20
EPROM Distance (mm) : 15 (0,59 inch)
Core Memory was also used in the Western Electric #1, 101 and #2 ESS Switches and the Automatic Intercept System (AIS).
Similar Core Memory planes were also used in DEC Minicomputers.
For the delectation of Raspberry Pi users - This image may be freely used for non commercial purposes :-) see the creative commons licence.
This image is a treasure trove.
The poster on wall on left is for a PDP-11/23, which was one of "a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the 1990s". en.wikipedia.org/wiki/PDP-11. Specifically, it is the PDP-11/23, "a second generation of LSI (F-11). Early units supported only 248 kB of memory."
The four fanned pennants behind the seated guy's head seems to be a motivational giveaway for a Digital Equipment Corporation conference held on August 15, 1979. I can't find any info on this.
The item on the far right is a "coming soon" poster for "A New Standard of Excellence in 16-Bit Minicomputer Architecture"-- the PDP 11/44. From Wikipedia:
"PDP-11/44 — Replacement for the 11/45 and 11/70 that supported optional cache memory and floating-point processor, and included a sophisticated serial console interface and support for 4 MB of physical memory. The design team was managed by John Sofio. This was the last PDP-11 processor to be constructed using discrete logic gates; later models were all microprogrammed."
Lastly, the book underneath the plans they're reviewing is "The Silva Mind Control Method"
Entry in category 1. Object of study; © CC-BY-NC-ND: Valéry Héritier
What could be more frightening to see robots and their artificial intelligence coming? We must also look at the positive aspects, such as this prosthesis, which will help amputees to regain pleasant living conditions. A sensor is used to pick up the muscles in order to translate the desired gesture on the robotic hand. Research is in progress.
By unpacking the robot we discover that it is composed of different electronic elements that are connected to a minicomputer that provides the algorithms necessary for the correct execution of the amputee's movements.
This photo was taken on the spot during a real test.
Page 34: Altair 680
These pages, featuring minicomputer kits and peripherals from the MITS Altair product line, were originally clipped from the December 1975 issue of Popular Electronics magazine.
Released in 1976, the DEC PDP-11 minicomputer was one of DEC's best selling lines. For $10,000 you could get this state of the art machine, complete with a 15 Mhz processor and 256 KB RAM. If you needed more storage space, you could buy a hard disk, with each platter storing 2.5 MB of data. Easily enough for anyone.
Read more about Bletchley Park and The National Museum of Computing
Swedish National Museum of Science and Technology.
From Wikipedia:
"The 12-bit PDP-8 was the first successful commercial minicomputer, produced by Digital Equipment Corporation (DEC) in the 1960s. DEC introduced it on 22 March 1965, and sold more than 50,000 systems, the most of any computer up to that date.
The earliest PDP-8 model (informally known as a "Straight-8") used diode-transistor logic, packaged on flip chip cards, and was about the size of a small household refrigerator.
This was followed by the PDP-8/S (depicted) , available in desktop and rack-mount models. By using a one-bit serial ALU implementation, the PDP-8/S was smaller, less expensive, but vastly slower than the original PDP-8. The only mass storage peripheral available for the PDP-8/S was the DF32 disk."
LASER DOPPLER VELOCIMETRY (LDV) USED TO MEASURE VELOCITIES IN A DIFFUSION FLAME.
SCIENTISTS USE ADVANCED LASERS AND COMPUTERS AT THE 50,000 SQUARE FOOT, FOUR-BUILDING COMBUSTION RESEARCH FACILITY TO STUDY EXACTLY HOW AND WHY FUELS BURN. IN THE LABORATORY BUILDING, SPECIAL LASER SYSTEMS WITH BEAMS ARE DISTRIBUTED TO 14 INDIVIDUAL LABORATORIES. EACH LABORATORY IS SERVED BY A MINICOMPUTER WHICH IS CONNECTED TO A CENTRAL DATA SYSTEM. IN ADDITION TO BENCH-TOP FLAME STUDIES, THE FACILITY HOUSES SEVERAL MAJOR COMBUSTION EXPERIMENT LABS, INCLUDING FIVE OPTICALLY PORTED RESEARCH ENGINES, A COMPUTER-CONTROL- LED COMBUSTION BOMB, AND LOW-PRESSURE FLAME, COAL FLAME, AND TURBULENT FLAME LABORATORIES. THESE STUDIES COULD LEAD TO THE DESIGN OF HEAT ENGINES AND ENERGY SYSTEMS THAT BURN FUEL MORE EFFICIENTLY WHILE CREATING LESS POLLUTION.
For more information or additional images, please contact 202-586-5251.
Si fa un gran parlare del Raspberry Pi : un minicomputer da $25. È un vero e proprio computer con sistema operativo Linux, processore ARM a 700MHz, porta USB e qualche extra a pagamento (Slot SD, porta Ethernet etc.). In pratica è una scheda madre miniaturizzata (maggiori info sul sito ufficiale ). ... Post originale: pasqualeborriello.com/raspberry-pi-e-davvero-una-rivoluzione