ALF Products
ALF Products Inc., or ALF, was a Colorado company primarily known for its computer-controlled music synthesizers and floppy disk supplies and duplicators.File:ALF Products First Logo.jpg|thumb|ALF Products' first logo. The line drawing, which was done using a computer plotter, is of a hypercube or tesseract.
History
In 1971 Tim Gill, a Wheat Ridge High School student with an interest in computers, visited the computer terminal room at Lakewood High School looking for "other intelligent life-forms". There he met Philip Tubb, a Lakewood High School student, who shared his interest in computers. This meeting inspired Philip to start the Jefferson County Computer Club. As a freshman, Philip had served as Student President, and he had good relationships with the school's and district's staff. He was able to create the only student-founded multi-school club in the district. Using log-on messages on the county's Hewlett-Packard 2000-series time-shared computer system, club meetings were announced county-wide and held at various high schools.At the Jefferson County Computer Club, Philip Tubb met many other students who shared an interest in computers. He also shared a strong interest in electronics with John Ridges, a Wheat Ridge High School student. John designed and built one of the first computer-controlled music synthesizers, a polyphonic unit with 6 voices. It could be controlled by a remotely located computer when connected between a teletype and its modem. The ASCII serial data flowing on that connection was used to issue commands to the synthesizer. John also wrote programs in BASIC which allowed music to be entered in text format, saved on the computer's hard drive, and played back using the device. The synthesizer got the nickname "Mesmerelda" due to the hypnotic effects of its status LEDs during playback.
While a student at Lakewood High School, Philip Tubb was hired part-time to operate the district's computer. In that job, Philip also taught seminars on programming to many of the county's high school math teachers who, with little if any prior instruction, were struggling to teach the programming classes. With those contacts, Philip and John began demonstrating Mesmerelda to music classes at several high schools, introducing the students to this new concept of computer-controlled music. Many of the students were interested in music but not skilled enough to perform using a conventional instrument. These students were excited by the idea of using a computer to play music, eliminating the need to master an instrument first. The potential market for computer-controlled synthesizers was apparently larger than the two had assumed.
After high school, Philip Tubb joined fellow former computer club members Tim Gill and Rich Harman at the University of Colorado. Philip soon discovered the computer science classes were based almost entirely on mainframe computers, which he considered obsolete by that time. He dropped out after one semester to study programming independently. Late in 1975, Philip began discussing the idea of starting a company to make computer-related electronic products with John Ridges. Colorado law at that time required an incorporator to be 21, and required at least three directors. Neither Philip nor John were 21 years old; Rich joined the project and signed the incorporation paperwork for "A L F Products Inc." in November 1975. The three served as the board of directors at ALF through 1992. The name "ALF" was chosen from a list of assembly language instructions for the Hewlett-Packard computer. It stands for "rotate the A register Left Four bits". This particular instruction was chosen largely because the letters have no curves and would therefore be easy to draw with a plotter or other line-vector graphics device.
ALF developed miscellaneous products before doing more serious work on computer-controlled music synthesizers. Several former Jefferson County Computer Club members became ALF employees, including Tim Gill. ALF created several products for the Apple II computer. Tim Gill wanted ALF to work on products for the new Apple III, but Philip Tubb had concerns about the viability of that computer. Tim soon left ALF to start Quark, Inc. and wrote Word Juggler for the Apple III. Despite this parting, ALF and Quark maintained a relationship over the years. One item ALF manufactured for Quark was a keyboard enhancement circuit that allowed Word Juggler to be used with the Apple II.
ALF was known for its whimsical advertisements and subtle humor in owner's manuals and product brochures. ALF's "Rock Star" ad noted that "Some companies will say anything to sell you a music card" and proceeded to ridicule selected quotes from competitors' ads. One of the quotes was actually from one of ALF's own earlier ads. The "guitarple" in the ad is not a real instrument; ALF constructed it only for the photo shoot. ALF's "Craftsman" advertisement was featured in Creative Computing's 1980 April Fools issue. The magazine, when turned upside down, appeared to be "Dr. KiloBYTE's creative Popular Personal Recreational Micro Computer Data Interface World Journal", a take-off on the names of several computer magazines at the time. This issue included 73 pages of humorous articles, with all the pages numbered in hexadecimal; ALF's ad appeared on page 3F.
As computer-controlled music became more and more popular, much larger companies began entering the market. ALF decided to switch their focus to equipment for duplicating floppy disks, which had little competition, and became a dominant supplier in that field. As compact discs began to replace floppy disks, ALF realized a larger partner was needed for that market. A buyout by Rimage Corporation, who had recently completed their IPO, was negotiated. Most former ALF employees left soon after the acquisition; Philip Tubb and John Ridges remained with Rimage for a few years.
Products
Early products
ALF's first products were adaptations of the punched tape reader in the Model 33ASR Teletype which allowed it to operate at higher speeds. Display-based terminals were becoming popular for use on time-shared systems, and they could operate at higher speeds than the Teletype. ALF created an interface card which allowed the Teletype's reader, which normally reads 10 characters per second, to read at 30 characters per second when used with a display-based terminal. It was sold only to schools in the local district; no attempt was made for larger marketing. Another version allowed the reader to operate at 55 characters per second, but modems that could operate at such speeds were not widely used at that time.Next, ALF produced a number of incidental S-100 products: a card extender, which facilitates testing an S-100 card by raising it above the other cards in the computer; an S-100 motherboard; an S-100 motherboard testing card, which simplified checking for assembly errors on a motherboard; and a random number generator. The motherboard testing card was sold though local hobby-electronics stores, and the motherboard was used in a subsequent product.
AD8 Music Synthesizer
ALF's first computer-controlled music synthesizer, designed in 1976–1977, was called the AD8. It was intended for use with any S-100 computer, but could be used with any computer via a parallel bus. The primary hardware was a one-voice synthesizer card; up to eight cards could be used to create a polyphonic system with one to eight simultaneous voices. A controller card, which had its own 6502 processor, connected to the user's computer and the synthesizer cards. Each one-voice card had the following controls:- An 8 octave range
- Volume control with 256 levels
- Two programmable waveform generators
- * Scanned-RAM D/A with 64 elements
- * 256 amplitude levels per element
- A low-pass filter with 16 levels
- An envelope generator
- * Rise rates of 0.004 to 1.3 seconds in 256 steps
- * Fall rates of 0.003 to 7.8 seconds in 256 steps
- * 256 sustain levels
- Stereo channel selection
ALF created a demonstration record, "Computer Controlled Synthesizer Performances", containing performances from Mesmerelda and the AD8.
Costing almost twice a much as the Altair 8800 or similar computer required to control it, the AD8 was too expensive for most hobbyists at the time. Few systems were sold.
Quad Chromatic Pitch Generator
Around the same time as the AD8, ALF sold a simple pitch generator card in two versions: one that plugged directly into an S-100 computer, and one that could be connected to any computer via parallel interface. Each card could produce four simultaneous voices, and multiple cards could be used in an S-100 system. There were no controls other than pitch. It could serve as a computer-controlled sequencer by connecting the individual voices to external equipment, such as conventional analog synthesizers. Additionally, a standard audio cable allowed connection to an ordinary audio system.Apple Music Synthesizer / Music Card MC16
The S-100 computers that customers used to control the AD8 or Quad Chromatic Pitch Generators varied widely in configuration; there was no single standard for even major items such as the type of display, keyboard interface or layout, tape device for software distribution, and so forth. This lack of standardization was a significant obstacle to ALF creating user-friendly software for their products. When Apple introduced the Apple II in 1977, it was available with only one display and keyboard format, which allowed software to be created that would work for all users. Unfortunately, the Apple II was less powerful than most S-100 computers and the accessory cards it could accommodate were physically quite small. It was necessary for ALF to design a synthesizer much simpler than the complex AD8.ALF used the AD8 to simulate a wide variety of possible synthesizer designs. These ranged from very simple ones much like the Quad Chromatic Pitch Generator to far more complex schemes using nearly the full capabilities of the AD8. These simulations could be operated in real-time and their Relative Enjoyment Factor measured to determine how usable each design would be as a functional music synthesizer. The target goal was a REF above 80. Numerous designs were evaluated and considered along with their estimated production cost. Finally, a design retaining the 8 octave range, accurate tuning, and a combination of ADSR envelope and volume control was selected; the programmable waveform generation and filtering functions of the AD8 were omitted. The final REF achieved was greater than 82.
The product was originally sold as "ALF's Apple Music Synthesizer", but Apple was concerned that customers might think the product was sold by Apple rather than being Apple-compatible; ALF changed the name to "Music Card MC16". It was the first hardware music product sold for the Apple II, and was one of the largest selling hardware accessories for the Apple II for some time. The product was demonstrated to Apple and Apple dealers late in 1978, and volume sales began in June 1979.
The sophisticated software written by John Ridges for this synthesizer was the first to implement graphical entry for a personal computer music product. At the time, his music entry program was the largest Assembly Language program available for the Apple II, and one of the few programs to utilize Apple's hi-resolution graphics. It was also perhaps the first software for an Apple computer to use a graphical user interface with icons and pointing elements ; several years ahead of Apple's Macintosh. Since the Apple II had no mouse, the GUI was implemented using the Apple's "game paddles"; one moved an arrow to select the desired icon, and the other moved the selected icon to the desired position on the musical staff on the screen display. When entering a musical note, the sound of the note was simultaneously played by the synthesizer for confirmation that the correct pitch had been selected.
Advanced functions in the software allowed repeated sections of music to be played without entering them more than once, and allowed the notes to be played on multiple voices simultaneously for purposes of additive synthesis. Additive synthesis is normally performed using sine waves, but since no waveform generator had been included, each voice could create only square waves. Additive synthesis can also be done using square waves, but the range of possible sounds is more limited. Tests with the AD8 had shown that very interesting sounds could be created with square wave additive synthesis when each voice used slightly different ADSR envelopes and/or small shifts in timing. Therefore, the MC16 was designed with very fine ADSR control.
Each card could produce three simultaneous voices, each with an 8 octave range with excellent tuning accuracy and 256 envelope/volume levels with an exponential scaling. Each voice could also produce quarter tones. Two cards could be used for six voices or three cards for nine voices; with two or three cards the audio output was in stereo.