Lobo's Max-80

Hi all, Basically, I bought a bunch (40) of 80 Microcomputing magazines which are in pretty much mint condition. Every so often I type up interesting articles and post them to a couple of groups I am a member of. Since I am new here, I don't know whether this is allowed or not. If not, just let me know. A long read, but quite an interesting one. I was trying to keep this short, but I ended up typing up most of the article! Source: Page 122, 80 Microcomputing #42 (July 1983) - a Wayne Green Publication. Ignoring the adverts, the full length article about Lobo's (or Lobo Drives International, to give it it's full name) Max-80 computer is 4 pages long and is written by R.A. Langevin. I have attempted to give a summary of all the interesting bits. Read on.... Lobo Systems' Max-80 is an 8-bit microcomputer that supports LDOS and CP/M; has an impressive array of storage options, including floppy and hard disks; serial input/output; and both serial and parallel printer ports. In terms of versatility and performance per dollar, it's unquestionably a best buy in todays marketplace. The system is a natural upgrade for [TRS-80] Model I owners since it offers CP/M while preserving their investment in disk drives and in much of their software. It is also completely at home in a business environment. Not everyone, however, will appreciate this computer. Serious game players will find they can't use self-booting disks in the machine [what the?!]. In addition, although Model I graphics are supported and limited graphics are available in the CP/M mode, the Max-80 cannot presently display full-screen, high resolution graphics, a deficiency that makes it unsuitable for some business uses. The Max-80 is basically a single-board computer housed, with it's power supply, in an attractive, ivory coloured plastic case mounted on a steel baseplate. It complies with the radiation limits established by the FCC for Class A computing devices. Although this standard states that operation of complying equipment is likely to cause interference in residential areas, I have not encountered problems even with a television in the same room. The Max-80 is 17.5 inches wide and 10 inches deep. The top of the machine is 2 inches off the table top at the front and slopes gently upward [like my Amiga 600] to 3.5 inches at the top of the keyboard. The rear of the case holds a line fuse and all the connectors and switches [sounds familiar]. The internal power supply operates off 110-115 volts AC and is efficient enough so that a fan isn't necessary to keep the electronics cool [computers needed fans back then?]. The entire computer requires only 28 watts. Even after hours of continous operation, the case is never warm to the touch. The reset button is safely located at the rear of the machine. Except for an optional 64K bank of memory, the Max-80 is complete as it comes out of the box. There are no extra boards for disk interfaces, serial I/O, or video electronics. As a result, the machines original cost is its only cost. The machine is available with LDOS 5.1 and CP/M 2.2; much of the available [TRS-80] Model I and Model III software are supported as is 8-bit CP/M software. This combination of operating systems provides access to a larger software base than that of most competing machines. - CPU: Z80B @ 5.07 MHz (faster than TRS-80 I, II ,III & 12 and the Softcard Apple) - Realtime clock (years, months, days, hours and seconds, all accessible by software) with internal rechargeable battery - Keyboard features a 10-key numeric pad, 4 programmable function keys and a cursor- control block that includes a clear key. All ASCII keys are supported by auto repeat and the entire keyboard is fully debounced. - RAM supplied by one (or two) banks of 64K each, provided by 8 (or 16) Texas Instruments TMS 4164-20 chips. - Only 1 ROM which contains a small bootstrap loader that disables once the system boots. As a result, the modified LDOS supplied with the system loads the bottom 12K of RAM with the code that resides in ROM on Tandy or LNW [who?] machines. Consequently, currently available self-booting disks don't operate on the Max-80. - Separate gold plated card edges for connecting 5 inch and 8 inch floppy drives (both supporting single and double density, aswell as single and double-sided, disks) and are supported by the built-in controller in both TRS-80 and CP/M modes. A slide switch mounted adjacent to the 5 inch disk connector controls pin 32, permitting it to select drive 4 or, alternatively, to act as the side-select signal when using double-sided drives. Track counts of 35, 40, 77 and 80 are supported on 5 inch disks and the standard 77 tracks on 8 inch disks. - A hard disk interface is also included in the Max-80 and is available on a 50-pin, gold-plated card edge on the rear of the machine. This Shugart Associates Standard Interface (SASI) is designed to be used with an external controller. Both of the computers operating systems are presently configured to use Lobo Systems' Universal Controller and do not support other controllers without modification. - Maximum of 4 drives with LDOS, or 8 drives with CP/M. Since so many disk options are available they have included a DIP (Dual In-line Package) switch is provided on the rear of the case so you can boot from either a 5 inch (or 8 inch) floppy, 5 inch (or 8 inch) hard disk or a 5 inch (or 8 inch) floppy connected via the universal controller. (If you have the extra 64K of memory installed, it's possible to set up a ninth RAM: drive with 1K of directory space and 63K of storage space) - 5 inch disks can be formatted in Lobo's single or double-sided, double density format or in Osbourne, Xerox 820 or Omikron single density, single sided formats - 8 inch disks can be formatted in IBM single sided, single density and double sided, single or double density formats. - Serial I/O is provided from 2 independently programmable RS-232 interfaces (provided by a Z80 SIO chip, rather than a UART chip as in Tandy's machines) accessible through DB-25 connectors on the rear of the case. Either interface supports all standard baud rates up to 19,200 and can be used to drive a serial printer. - Parallel printer output is available via a standard Centronics interface, with a slide switch adjacent to the port which permits grounding or ungrounding pin 27 to adapt to printers (like the Epsom MX-80) that interpret a grounded pin 27 as a request to generate a line feed after each carriage return. - Video output is via a RCA phono jack and drives any monitor that accepts 1 volt composite video from a 75 ohm source and provides 15,750 Hz horizontal and 60Hz vetical sync frequencies. Lobo recommends a monitor bandwidth extending from DC to atleast 12 MHz to obtain good detail in the display, This is especially important in the CP/M mode, where the normal display is 80 characters by 25 lines. You can select a 40 character by 25 line display with a function key. In the TRS-80 mode, the display is a compatible 64 or 32 characters by 16 lines. - Standard TRS-80 Model I graphics are supported by the LDOS operating system - the extended graphics of the [TRS-80[ Model III are not. In the CP/M mode you can display up to 192 user-defined shapes. The first 128 shapes are limited to shapes that can be defined in the top half of a 8x16 pixel rectangle (and in normal use are used to display the ASCII character set). The remaining 64 shapes can be defined in a full 8x16 pixel rectangle. Max-80 with just 64K and CP/M 2.2 - $820 LDOS 5.1 - $69 64K RAM expansion - $95 Amdek Video 300 Green Screen 12" Monitor - $175 Regards, Andrew B aliensrcooluk at yahoo.co.uk