Classic Computer Magazine Archive CREATIVE COMPUTING VOL. 10, NO. 9 / SEPTEMBER 1984 / PAGE 12

Sanyo 555, small business computers. (evaluation) Jon Geist.

Sanyo 555 Small Business Computers

The Least Expensive of the PC Compatibles

Recently, Sanyo Business Systems introduced two new 16-bit microcomputers, the MBC-550 and the MBC-555. Many dealers are advertising these micros as cost effective IBM PC compatibles. More realistically, however, they should be viewed as machines intermediate in features between the PCjr and the PC, which can meet the needs of many users at a remarkably low price.

The MBC-550 package from Sanyo consists of a 16-bit, 8088-based, single board computer with 128K of RAM, a 5 1/4 disk drive, a keyboard with five function keys and a numeric keypad, color graphics capability, and a software package with Sanyo Basic, MS-DOS 1.25, Easywriter, WordStar, and CalcStar.

The MBC-555 package includes an additional disk drive and SpellStar, MailMerge, and InfoStar. Some dealers, mostly mail order houses, are adding a monochrome monitor, printer, second disk drive for the 550, or some combination of the above to sweeten the deal. A second disk drive makes a 550 into a wild after its wing mended in

As this article is written, the 550 is selling for well under $1000 and the 555 for not much more. Clearly this represents a great deal of computer power for the dollar. One way to assess value of the 555 is to realize that a comparably equipped IBM PC costs about $3400. The 550 Series prices are so low for a 16-bit machine that they offer substantial savings compared to the most inexpensive of the PC compatibles, and even the PCjr.

Another way of looking at the value of the Sanyo MBC-550/555 is to realize that most comparably equipped systems based on 8-bit computers cost as much, and many cost even more. Moreover, the 8-bit systems are limited to 64K of Some specialize in raptors, others in

So the real question is this: What do you give up when you buy one of these computers instead of a comparably equipped IBM PC or PC compatible, and is the loss worth the monetary savings?


First, it is important to understand that the 550 Series is not fully compatible with the IBM PC. Probably the most important difference between the 550 Series and the PC is the way in which they address the memory map of the monitor screen. As a result, any software written for the PC that uses graphics or a screen editor probably will not run to its full potential as the 550/555. More about this later.

One weakness of the MBC-550 Series hardware as presently packaged is that it uses single sided disk drives, just as the IBM PC did when it was first introduced, rather than the double sided drives now standard with the PC. Thus, its disk capacity is only 160K of storage rather than the 320 available on the PC.

On the positive side, the Sanyo machine does use the same disk format that the PC uses for single sided disks, so it does read disks written on the PC as long as they were formatted using the single sided format option.

Eassentially, the MBC-550 Series is data compatible with the IBM PC (like the TI Professional) rather than functionally compatible like the Eagle, Corona, Columbia, and Compaq. To see what limitations this might impose in any particular application, it is necessary to look at the computer itself, its keyboard, and it software in some detail.

The System Unit

The MBC-550 consists of a stamped steel chassis housing the single board computer, and a detached keyboard. The chassis is about 15 across by 14 deep by 4 3/8 high. This is a little larger than the PCjr chassis and about 3/4 the size of the PC chassis in each dimension. It has a simulated stainless steel finish with a pleasantly functional appearance.

The front panel is plastic, but it matches the steel top panel perfectly. There we found an on/off switch, a TEAC FD-55A single sided, double density, 5 1/4 disk drive, and a compartment for disk storage. The compartment fills the space reserved for a second drive.

The fact that the system unit can accommodate two disk drives is a significant advantage over the PCjr, but the choice of single sided drives is a disadvantage. Obviously, there is some cost advantage to the single sided drives, and it is clear that Sanyo designed this system for high performance at low cost.

Drive A is on the right. This is unconventional by American practice, but causes no problems because each drive is identified by an embossed letter just below it. Next to the letter that identifies the drive is an icon of a small disk oriented properly for insertion into the drive. This should be a help to new and infrequent users.

The chassis encloses the single circuit board. Hard wired onto this board is an 8088 processor, 128K of dynamic RAM, and the circuitry to control a parallel printer port, RC-232C serial port, joystick, composite video monitor, color graphics, and double or single sided disk drives.

The MBC-550/555 comes with the video monitor and parallel printer ports already wired to external connectors on the rear of the chassis. However, the connectors and cable for the joystick and serial port must be purchased separately.

The circuit board has sockets for 16 4164 dynamic RAM chips to expand the onboard memory to a maximum of 256K. A socket is also available for an 8087 numerical coprocessor, but no other expansion sockets are available within the 550/555 chassis.

There is a 62-pin connector on the circuit board with 48 of the 62 IBM PC I/O expansion lines connected to it. This is a good feature, allowing considerable expansion of the capabilities of the 550 Series through the addition of an external chassis to contain third party hardware originally developed for the IBM PC. But, this capability would have been enhanced considerably if some of the remaining 15 lines had been connected.

The missing lines are the -5 volt supply line, all lines involved in the memory refresh cycle, all lines involved in direct memory access (DMA), and all but one of the user defined I/O interrupt lines. The absence of the -5 volt line is no great loss, but the loss of the other functions is significant.

Could the lack of those extra I/O functions be a reason not to buy a 550? If the computer is being purchased only to do the things that it already does, then I/O expansion capability is of little or no concern. Since even the most powerful 16-bit machines will probably be rather limited compared to the 32-bit machines that are planned for introduction over the next few years, this may be the most reasonable attitude toward expansion. But I assume that you are looking for a computer now, so if you want a computer that can grow in power and capability, you should be seriously concerned about differences in growth potential between the 550 Series and some of the more expensive machines.

Despite the limitations pointed out above, the 550 Series is capable of a great deal of external expansion. Thoughtworks in Phoenix, AZ already has 5, 10, and 20Mb hard disk drives for the MBC-550 Series that can be purchased at prices ranging from $2200 to $3600. Memory expansion cards for the PC that use static RAM should be easily interfaced to the 550/555, while cards using dynamic RAM would require a significant engineering effort because of the necessity to synchronize their refresh cycle with the internal clock of the computer.


The keyboard is a nice feature of the MBC-550 Series. It looks and feels more like an IBM Selectric keyboard than does the keyboard on the IBM PC, but still differs significantly from the Selectric layout around the edges. The DELETE key is in the right place with respect to the RETURN key, but the RETURN key, while conveniently large, is located one key far to the right. The keyboard is by no means quiet, but it is considerably less noisy than the PC keyboard. It also has a less metallic and squeaky sound.

The keyboard differs from the PC keyboard in several other more substantial ways. It has a hard reset key in a protected, but readily accessible location on the left side, and it has no ALT key as a true PC compatible would. Instead, it has a GRAPHICS key that works like a shift lock key. The first time it is struck, the keyboard enters the graphics mode and a red light on the key comes on to remind you that you are in the graphics mode. To exit this mode the key is struck again.

In the graphics mode the various key strokes, including shift-modified and control-modified strokes, are assigned alternate characters. All of the characters in the IBM extended ASCII set having decimal codes from 32 to 255 are available as keystrokes using either the normal or the graphics mode. Characters having ASCII codes 1 through 31 are not available as keystrokes, presumably because these ASCII dodes are also assigned to control functions such as linefeed and carriage return.

In summary, the MBC-550 Series as delivered has more hardware capability in certain areas and less in others than a basic PC. Some of the expansion capability of the PC is already available for the 550 Series, and further expansions using hardware developed for the PC would be a rather simple job. Other expansions that are readily available for the PC, such as the production of a "smart' motherboard in an expansion chassis to implement functions not available from the 550 Series motherboard, would require a major engineering effort.

The 550 Series seems to be a more powerful computer than the PCjr, (except in the area of game support where the jr exceeds the PC itself). However, the jr can almost certainly run more PC software.

It is worth noting that Sanyo hardware has a good reputation for reliability. One of the local dealers in my area claims to have had fewer problems with Sanyo machines than with any other brand that he carries. Of the 200 8-bit and 60 550 Series computers that he has sold, only three have come back for hardware problems, and these were all easily fixed in his shop.

In closing this discussion of hardware and expansion capability, we point out that many PC's will never be expanded to equal the 555 as delivered. From this point of view, the 550 is a real bargain. In fact, when you consider the software that is included in the bundle, you might feel as if you were buying a keyboard, a color graphics board, a disk drive or two, and the software, and getting the actual computer for free.

Software Support

This brings us to the question of software. The MBC-550 Series may offer hardware power comparable to that offered by the PC compatibles, but it cannot be considered a comparable machine if there is a software package ideally suited to your task that runs on the PC, but is not available for the MBC-550.

Because the MBC-550 Series is very new, and because it is not functionally compatible with the IBM PC, there is not much software beyond what is bundled with it that will run on it at this time. Several companies are writing software specifically for the 550 Series, and Sanyo has released a list of 70 packages from about 20 companies that do run on the 550. Still there is a great deal of PC and generic MS-DOS software that doesn't run to its full potential because of problems with screen editors and graphics.

The software problem is currently more serious than it need be due to three more fundamental, but hopefully temporary, problems. The 550 Series Basic Input-Output System (BIOS) is not currently as PC compatible as it could be. There is little documentation currently available for 550 Series, and much of what is available leaves a great deal to be desired.

The BIOS, which is the source of some of the current software compatibility problems, is the machine language program that interfaces the CPU, memory, and all input and output devices. Thus the BIOS for each different type of machine must be different to reflect the details of machine hardware.

Software that uses a screen editor, such as a word processor, expects to be able to send control characters or characters following an escape character to tell the BIOS how to move the cursor, and whether to delete, overwrite, or insert. It is possible to write this sort of software using only the commands supported by the 500 Series BIOS, but generic MS-DOS software often expects the BIOS to support direct cursor addressing. This may not be a true system call supported by MS-DOS, so it may not be quite fair to expect this type of support. But finger pointing does not change the fact that this type of generic software is being written, and the 550 Series should run it.

Borland's new Turbo Pascal is an excellent example. The version of Turbo Pascal that is written for generic MS-DOS will compile and execute programs without any problems on the 550 Series, but its screen editor requires a richer variety of control commands than Sanyo has provided. Thus, one of the many outstanding features of Turbo Pascal, the convenience of a powerful, built-in screen editor, is lost by running the generic MS-DOS version of this language on the MBC-550. That's the bad news.

The good news is that the PC-DOS version runs perfectly on the MBC-550. But it is important to understand that this is not the case with all software written for the PC. The fancier the graphics and screen editing capabilities of a particular piece of software, the more likely it is that it will depend upon some feature of the PC hardware or BIOS that is not available on the MBC-550.

There are other deficiencies in the BIOS as well as the lack of direct cursor addressing. There is no interrupt for a screen dump, for example, which is a significant disadvantage, and there is only one video mode, which is a tradeoff. The single video mode combines the text and high-resolution (eight colors, 640 X 200 pixels) graphics modes of the PC. This is a disadvantage in that it reduces compatibility with PC software, but it simplifies the use of graphics and other operations with software written specifically for the 550 Series.

While it is true that the BIOS of the 550 handles software written specifically for it with no problems, the 550 Series would be considerably more powerful and would run more software better, if it had a better BIOS.

Bundled Software

Two word processing packages are bundled with the MBC-550/555, Wordstar, Version 3.3 from MicroPro and EasyWriter Version 1.3 from Information Unlimited Software. Both work well, are well documented, and have well written training manuals.

IUS deserves special praise for their implementation of Easywriter on the 550. They took maximum advantage of the features of the 550 keyboard to create a word processor that is both easy to learn and easy to use. Readers familiar with earlier versions of Easywriter might be interested to know that version 1.30 has some enhancements that make it considerably more powerful and easier to use than earlier versions. But both the ease of use and the ease of learning are further improved by the way this word processor fits the keyboard. This sort of optimization is not possible with a program designed to work on several different machines.

There is not a great deal that I can say about anything other than WordStar and SpellStar in the software package from MicroPro. I have no real experience with spreadsheets, computer mailings, business form generation, and business data sorting, all of which are supported by this package. I have tried the various programs out to see how they work, and I have thought of few applications that I may have for them in the future. But I can't really comment intelligently on them, other than to say that they seem to work in the way expected.

Microsoft's MS-DOS 1.25, and the disk-based utilites, CHKDSK, COMMAND, DEBUG, DISKCOPY, EDLIN, FILCOM, and FORMAT are included in the bundled software package as the operating system. Chapter 4 of the Sanyo MBC-550 Series Operator's Guide, which is titled MS-DOS Introduction provides no help in using this operating system beyond the most basic operations. Not even the purpose of COMMAND, DEBUG, and FILCOM are mentioned in this chapter, much less their use. For some reason EDLIN and EXE2BIN (a utility that is not provided) are described in outline form. It is unlikely that anyone who did not already know how to use them, would ever guess what their use is, much less how to do anything useful with them based on the information provided. The last page of the Operator's Guide refers the interested user to Microsoft's MS-DOS Reference Manual for further information. One of the many texts on PC-DOS and MS-DOS might be even more useful, not to mention less expensive.

Sanyo's version of Microsoft Basic-80 with graphics commands is also part of the software package. Like IBM's BasicA and Microsoft's GW Basic, Sanyo Basic for the 550 Series was cross compiled for the 8088 from the 8-bit 8080 code for Basic-80. It even shares some bugs with the early versions of these other Basics. However, its graphics commands have somewhat different syntax, and it does not have as rich a set of commands. With very few exceptions the missing commands are not a serious loss. For instance, Sanyo Basic has a screen editor, but no line editor, and it has only one command (rather than the two redundant commands of BasicA) for opening ASCII files.

Chapter 3 of the Operator's Guide, which is titled Sanyo Basic, is no better than the chapter on MS-DOS. What is in this chapter is reasonably well described. But most (or at least half) of Basic is missing. You will never find out how to read and write data to disk files in ASCII format, much less in random format from this chapter. You will never find out how to execute program overlays or to work with user defined print formats. Nor will you find out how to use PEEKs and POKEs or to write machine language subroutines. You will never even find out how to use most of the built-in functions.

This might not be a problem if the Sanyo MBC-550 Basic Reference Manual were available. But as of this writing, it has not yet been released. However, a Microsoft Basic-80 Reference Book or Reference Manual, and the List of Reserved Words in chapter 5 of the Operator's Guide, in conjunction with chapter 3 is more than adequate to enable you to use the full potential of Sanyo Basic. A manual for BasicA or GW Basic could also be used if you can find one to purchase.

In either case, it is advisable to modify the commands in the manual that you do use to reflect the differences between the version of Basic described in the manual and the version you are actually using. For instance, the DELETE option is not available in the CHAIN command in Sanyo Basic on the MBC-550 Series, but except for this omission, the CHAIN command works exactly as described in the Basic-80 Reference Manual.

The remaining four chapters of the Operator's Guide: Getting Started, Glossary, Technical Reference, and Peripheral Installations get mixed reviews. The first and last chapters are not bad. Both present the expected information in a concise, understandable manner accompanied by ample clear illustrations. A user with very little experience should have no trouble getting MS-DOS running and making back-up copies of all of the software supplied with the package following the step by step instructions in the first chapter.

The technical reference chapter is a mixed bag. More information would be desirable, but there is a great deal of useful information in this chapter. Unfortunately, it is not organized in any logical way, and much of it should be in other chapters. But, at least it is available somewhere. A description of how to install a screen editor to the extent that the BIOS will support it would have been a useful addition to this chapter.

The Glossary chapter is not very useful, being incomplete and, in places, incomprehensible. For instance, we find that a printed circuit board is "the real estate for electronic circuits. Sheets CIRCUIT BOARD [sic] of fiber glass or epoxy with copper conductors etched onto the surface. Components mount onto the traces,' as well as more useful information that might help when reading other parts of the manual.


In summary, the MBC-550 is a very powerful computer for the money. In this regard, nothing else comes close. Whether all of its hardware power will be usable depends upon the quantity and quality of the software that becomes available for it. This, in turn, depends upon two factors: the number of people who actually buy this computer system and the amount of generic software and software written for other computers it can run.

The MBC-550 is no different from any new machine that is not a software compatible up-grade. Right now there is even less software available for the Macintosh than there is for the MBC-550. It will be interesting to see which machine is better supported in the long run. There is much more effort being devoted to the Macintosh, but that conversion is more difficult. All that is needed for the MBC-550 is a BIOS that provides better support for generic MS-DOS software. Of course, a BIOS that emulated the PC BIOS would be even better. However, because of the hardware differences between the two machines, this is probably not possible without a smart expansion box.

The only sure thing at this point is that if the MBC-550 catches the public's imagination even without a broad software base, one will soon appear. This, of course, applies to any new computer. If it does happen, a broad base of expansion hardware support will also appear, and in retrospect, it will be clear that the 550 was one of the best buys in the history of small computers.

On the other hand, buyers could just as easily find themselves with a system that is virtually without software and hardware support beyond what exists right now. If this is the case, the 550 may not look like such a good deal a few years hence, when the PC compatible machines are doing things that are just a gleam in the eye right now. Both of these scenarios are extreme, but they define the limits. In this field, no better predictions can be made.

In any event, if you are considering a computer purchase now, you owe it to yourself to consider the MBC-550 to see if it can do the things that you want to do now, and to see how much of a gamble is involved with respect to your goals for future expansion. You may want to take the gamble. If you are currently considering a system with a disk drive, it won't cost much more to go with the MBC-550 than with a Commodore 64, and the 550 is a much more powerful and versatile machine.

Products: Sanyo MBC-555 (computer)