[author : Jim C. Warren, Jr.] #Audio
A systems project uniquely appropriate for your home computer
Extract : « Do you use tape recorded music in your home music system? Do you have a number of bands or "cuts" recorded on a single tape? Wouldn’t it be dandy to be able to play only desired cuts without having to manually hunt for each one, and then have the tape automatically rewound when a side is finished? You can do it with your personal computer; a project uniquely appropriate for home computing.
How you can use the system: Mount the desired stereo tape on the tape transport. Tell your computer which bands are to be played. You may instruct that they be played in a different sequence than they appear on the tape, and you may have any cut(s) played more than once. Tell your computer whether or not to rewind the tape when finished. Then, do nothing but enjoy the concert of selected pieces until the computer is finished with the tape. The computer will use the fast-forward / fast—reverse facilities of the tape transport to move between selected cuts that are nonsequential.
The following notes outline how such a system can be implemented at nominal cost with currently available components. [...]
*A realizable fantasy is a project that has not yet been done, but it's time to do it. That is: (1) It's interesting, entertaining, and/or useful. (2) It's feasible for hobbyists in that it can be done in a reasonable amount of time, at reasonable expense, and does not require great expertise (except, perhaps, that which can be furnished in the design article). (3) It is well within the limits of current technology and current techniques. Send us your realizable fantasies, so that we may share them with others. »
[author : Jim C. Warren, Jr.] #Audio
A survey of computer speech synthesis systems including a $395 completely assembled unit
Extract : « Intelligible, useful, voice synthesis by home computers is now available to hobbyists at reasonable cost. This means that, not only can your computer talk to you and your spouse (who, admittedly, may not want to hear it), but it can also talk to your pre-reader and beginning-reader children. Thus, besides being fun and useful in a general context, your home computer can also become a significant educational tool for young children.
There are several manufacturers of computer speech synthesis subsystems, two of which are marketing specifically to hobbyists, and one of which is worthy of specific attention.
The best system we know of for hobbyists—i.e., financially feasible—is nearly available from CompuTalker Consultants [...] »
#OpticalInput #Memory
Extract : « A major manufacturer offers significant discounts to hobbyists on memory & a 1000 cps tape reader
Plessey Memories and Plessey Microsystems is the first large manufacturer, traditionally marketing its products to major industrial purchasers, that is making its very significant GSA (U.S. General Services Administration), and Educational discount schedules available to hobbyists.
They offer a 1000 char-per-second paper tape reader, including electronics and buffering, to hobbyists (and Educational, and GSA customers) for $340. [...] »
[author : Walt Ferris] #ComputerKit
Extract : « Dear Jim,
We plan to make a Hobbyist-Standard (Altair/IMSAI compatible) card which will add new commands and addressing modes, some of which will match or better the Z-80 commands.
We would like your opinion on what is desirable. Some of the possible extensions are listed below. If some variation seems more appropriate, as an addition or as a substitution, please mention this. Notes about any other function you wish added will be appreciated.
Of course, the more we put in, the more it costs. And there is the basic question is it worth it, since existing software would have to be modified to take advantage of it. [...] »
#Memory
Extract : « 256K byte core memory for $6500, Dataram Corp. [...]
8K memory includes battery backup, Seals Electronics [...]
65K bit CCD's from T.I., Texas Instruments [...]
65KB CCD's from Fairchild... sooner [...]
64K CCD board for $1500+ by end of year, BISI [...] »
#Education
Extract : « The University of California is soliciting advice from vendors of computer equipment and programs. This is an opportunity to consult with us in advance rather than tell us what we should have done after the fact. We are earnestly seeking your best thinking prior to considering the publication of a Request for Proposal which will establish our direction for the near future. This document is not a Request for Proposal (RFP) but rather an invitation to share with us your ideas and recommendations whether they be basic or "blue sky." Your response to the Request for Information (RFI) is voluntary and does not commit either you or the University.
The University wishes to dramatically improve the system of delivering computing capability to the 120,000 students on the nine campuses and associated sites. Instructional capability has been provided through both batch and timesharing services utilizing existing large computers housed in a computing center located on each campus. In the last two years, several of these centers have installed timesharing minicomputers which allow for the connection of several (typically, 16 to 32) remote terminals, through which the student may write programs in BASIC or access prewritten programs provided by an instructor ("Courseware"). These minicomputer-based timesharing systems have proven to be very effective and they have the capability of expanding the services to meet academic needs. Such systems are flexible enough to meet a very large percentage of the needs of a very large percentage of the students.
We feel that, now, with the changes being brought about by improvements in chip technology and the corresponding explosion in microcomputer capability, even lower cost solutions may be possible without giving up anything in capability. With any timesharing system, unless all terminals can be hard-wired, there will be additional costs (beyond the computer and the terminals) for modems and communications lines. Technology has been producing orders of magnitude improvements in price/performance of computers, but communications costs are rising. Therefore, it seems prudent to search for solutions regarding delivery of computing which do not depend vitally on communications. Such a model might be found in a single-user machine with the following design goals: [...] »
[author : Jef Raskin] #ComputerKit #Tips
A critique of "little hidden gotchas" found in a multitude of kits
Extract : « Let it be known: the computer for everyman is not here. Yet. Caveat Emptor! The tempting price tags you see in the ads are a mere drop in the wallet. These are not Heath kits - you need a good bit of understanding of electronics and some about software to use them. Either that or a lot of patience and good learning habits, or a friend who knows what you don’t. Of course, you could wait until Heath does come out with one [which should happen by the time you read this.—Editor].
Having bought and built the two biggest names in the personal microcomputer field, the Altair 8800 and the IMSAI 8080, I know that there is much to praise. Both machines now run perfectly, reliably, and perform within their specifications as well as any computer I have worked with. They are dependable. I have purchased memories from Processor Technology, Dutronics, Solid State Music and Cromeco, a total of 52 Kilobytes, and all have operated, once debugged, without error, week after week. The same is true for my IMS parallel I/O board, the MITS SIO and 2-SIO serial boards, the PT Video board and so on. They all work. But, very few of them would have worked if I had not had prior electronics and computer experience.
Before I go on to details, I should mention that I write from the point of view of someone who wants to use the computers in various applications; not learn about computers per se. I chose the kits because they are cheaper than anything else currently available (which means until approximately next week) in the way of true general purpose computers. If you want to be forced to learn about hardware the hard way, the inadequate documentation (and just plain bad writing) that comes with almost all the personal computing products and the poor workmanship and parts of a few, will make you prematurely wise, and give you a bad disposition. [...] »
[author : Tom Pittman] #Listing #Assembly
Extract : « (Reprinted with permission from the Homebrew Computer Club Newsletter)
These two programs were designed to co-reside in 8K of RAM with 762 bytes of workspace remaining for edit buffer or symbol table. If you have more, your workspace is thus larger. Also, both the editor and assembler are designed to be able to use the other’s program space for additional workspace if desired. Figure 1 is a memory map of the system. The first two pages (locations 100-2B5) in these two programs are the same, and contain all of the I/O routines for both. If location 300 is non-zero, the Editor will use the assembler program space for additional buffer. The Editor is designed to use all available contiguous memory, but the Assembler will limit its symbol table to memory below 2000, or below the contents of 301-302. [...] »
[author : Steve Wozniak, Allen Baum] #Listing #Assembly
Extract : « DESCRIPTION
This subroutine package is used to display single or sequential 6502 instructions in mnemonic form. The subroutines are tailored to disassemblers and debugging aids, but tables with more general usage (assemblers) are included. The subroutines occupy one page (256 bytes) and tables most of another. Seven page zero locations are used.
FEATURES
Four output fields are generated for each disassembled instruction: 1) Address of instruction, in hexadecimal (hex); 2) Hex code listing of instruction, 1 to 3 bytes; 3) 3-character mnemonic, or “???” for invalid ops (which assume a length of 1 byte); and 4) Address field, in one of the following formats. [...] »
[author : Steve Wozniak] #Listing #Assembly #GamePuzzle
Extract : « DESCRIPTION
MASTERMIND is a number guessing game. In this version the computer generates a 5-digit, random number where the digits are limited to 0 through 7. The user attempts to guess the number in the fewest possible tries. After each guess the computer informs the user as to how many digits were correct (contained in the random number) and in the correct position by printing '+' signs, and how many digits are correct and in the wrong position with '-' signs. The user is not informed as to exactly which digit positions the '+' and the '-' signs correspond. A skilled player can usually win in 6 or 7 tries. [...]
RUNNING ON APPLE-1 SYSTEMS
The source and object listings provided will run on APPLE-1 systems. [...]
RUNNING ON OTHER SYSTEMS [...] »
[author : Marvin R. Winzenread] #Listing #Assembly
Extract : « If you have a Processor Technology VDM or any display that reads directly from memory and at least 256 bytes of other memory, here is a random walk program you might like.
The program was assembled using P.T.’s software No. 1 on a system of only 8K, so the comments were added later.
I hope you enjoy my turtle. [...] »
[author : The Penny Tiger] #Listing #Assembly #Programming #BASIC
Extract : « Dear Dr. Dobb,
I have implemented the Whipple/Arnold TINY BASIC [DDJ, Vol. 1, Nos. 1&2], and am really excited about the super job they did.
I have several modifications to it (any system worth having is worth modifying to your own desires). Most of the modifications are of interest only to me. However, a few modifications may be of general interest, so I am offering them to you to share as desired.
Since I am a programmer by profession, I owe my soul to the company store. So If you publish this, please sign me as - The Penny Tiger [...] »
[author : Richard A. Kaapke] #Listing #Assembly #Audio
Extract : « Dear Editors of DDJ:
I was indeed interested in seeing some modifications to Steve Dompier’s MUSIC PROGRAM [DDJ, Vol.1, No.3]. However, there is still an inconvenience in the original program. This is the necessity to change the tempo data in memory for each new piece that is loaded. I submit to you my re-written code that allows the user to input the tempo to the program from the sense switches of his machine, allowing him to change and “fine tune” the speed at which the music is played. The new code is as follows: [...] »
[author : F. J. Greeb] #Listing #Assembly
Extract : « Dear Jim,
I just finished looking through Vol.1, No.6, thought it was great, as usual, and decided to send along a few comments.
The following mod should be made to get dimensioned variables to work properly in my Denver version of Tiny BASIC [DDJ, Vol. 1, No. 3]: [...] »
[author : The Stanford Observer] #Cryptography #Encoding
Extract : « (reprinted with permission from May, 1976, The Stanford Observer)
The proposed key for a security system designed to lock up the vast quantities of information stored in U.S. computers so that only authorized persons can get at them is “too small” and “within 15 years will be rendered totally insecure” in the opinion of two Stanford computer experts.
Electrical Engineering Prof. Martin E. Heilman and graduate student Whitfield Diffie criticize the computer key, proposed by the National Bureau of Standards (NBS) and the National Security Agency (NSA), in an article in Communications of the ACM (March 1976), professional journal of the Association for Computing Machinery.
The two computer experts have been working on related research in data security under National Science Foundation sponsorship.
If the Secretary of Commerce approves it, the key will become a required standard for most federal agencies and a de facto standard for all computer users. [...] »