Sony SMC-70

The Sony SMC-70 (Sony Micro Computer, is that a bit like ATM Machine?) was my first computer. It’s a guess what the 70 represented. In 1980, Sony announced the Series 35 word processor, the first device to use their new 3.5″ floppy drive. 35 was chosen as the model number not because of the new floppy drive, but because the year it was released, 1981, was Sony’s 35th anniversary. It’s possible with 7 being a lucky number in Japan, they just doubled the model number of the word processor. Incidentally, in a nod to this machine, when they reentered the PC business in in 1996, the first model was the VAIO PCV-70 (Personal Computer Video), a system with a Pentium 166. The number 7 popped up a lot in machines from Japan in the 80s, including the Casio FP-7000, Epson HC-7, Fujitsu FM-7, Hitachi 70 Series, NEC PC-7001, Sanyo PHC-77 and PHC-70FD, Sharp MZ-700, and Toshiba Pasopia 7 and 700 (none were released before the SMC-70). They really liked the number 7!

The SMC-70 was both ahead of, and behind the times, when it was released in 1982. It was a color Z80 based system running CP/M at a time when not only color CP/M systems were rare, but color was rare in the computer industry. The Z80, the processor inside the SMC-70 was released 6 years earlier in 1976, while CP/M 2.2 was released 2 years earlier in 1980. Things were moving quickly in the early 80s. The 16’ish bit IBM PC was released the previous year in August 1981 and was now considered the benchmark for business computers, the market Sony was trying to enter. It was an odd time for Sony, as they were still developing word processors in parallel with the SMC-70, a word processor itself that could run CP/M, and therefore much of the same library of CP/M software as the SMC-70, as an option.

Color was what set the system apart. IBM’s CGA adapter, available in the Model 5150, could display 16 colors at 320×200, and 2 colors at 640×200. The SMC-70 was also capable of 16 colors at 320×200, but could display 4 colors at 640×200, and monochrome graphics at 640×400. The system had better color graphics than CGA, a higher monochrome resolution than MDA, and users didn’t have to make a choice between the two. Like other color palettes of the time, the colors of the rainbow weren’t available, and there wasn’t a palette of colors to select from (this came with the next model released a year later, the SMC-777), but Sony didn’t offer the standard CGA color palette either. The colors available were black, ash blue, dark green, deep blue, red, bright green, salmon, yellow, gray, light blue, moss green, turquoise, pale pink, brilliant pink, tan, and white.

At an announcement on May 17, 1982, Sony stated a list price of $1,475 for the SMC-70, which would fall to $995 by January 1984. The New York Times covered the announcement. The SMC-70G was announced on September 29, 1983 with a suggested retail price of “under $3,000”. Buying a computer in 1982 wasn’t like buying a computer today, so while that $1,475 purchased a capable machine, there wouldn’t have been much someone could have done with the machine other than make it beep! That purchase price didn’t include any floppy drives (or floppy drive controller), a monitor, or a cassette recorder. But the SMC-70 did come with built-in hardware that an IBM PC did not, including a serial port, parallel port, color and monochrome video, 48K of additional RAM, a real-time clock, and light pen support. Users were expected to configure both systems to meet their needs, Sony just included a bit more value for the money. Other options were similar between the two machines, such as a cassette port, and instead of a keyboard port, the SMC-70 had a port for an optional numpad. Considering this was sold as a business machine the numpad being optional was seen as an odd choice by Sony, but it’s possible they expected many users to buy the machine for word processing.

So, the second obvious purchase after the base machine would be a monitor.

What perhaps sets the SMC-70’s color capabilities apart from the few other color CP/M machines on the market was the Sony Trinitron monitor. While a 12″ long persistence green phosphor monitor with a built-in speaker was available (the Sony CPD-120) with a list price of $375 (often available for $280), the system was typically paired with the 12″ Trinitron KX-1211HG which had a list price of $895. Oddly, the monitor was named the KX-13HG1 in Japan, with a list price of $650 (after conversion). The monitor had a 0.39mm dot pitch, accepted both composite and RGB (analog or TTL) signals, and had a 15 kHz horizontal and 60Hz vertical scan range. It had handy (and sturdy) carrying handles on top, screw holes on the side to mount optional speakers, and a removable tinted glass front panel that improved the contrast but had to be removed to use the optional light pen (SMI-7061; $175).

For those with deeper wallets, the PVM-1270Q/1370QM, released in 1983, was a later option, with a 0.25mm dot pitch and a list price of ~$950. This monitor was often paired with the SMC-70G. The cable to connect the computer to the monitor was another $55 for the KX monitors (SMK-0001), and $90 for the PV monitors (SMK-0002).

By spending $2,425, a user could buy a computer with a color monitor and the cable to connect the two that included Sony’s System Monitor and Sony BASIC in ROM. Still not much you could do with your new system unless you wanted to type in a new program every time you started the system, assuming you knew how to do that!

If you actually wanted to know how to use your computer, that would cost you even more! The Micro Computer Operating Instructions (SML-7000) cost $12; one was supposed to be included with the system (my systems only contained the computer and packing material), the Sony BASIC Introductory Manual (SML-7001) was $20, the Sony BASIC Programming Reference Manual (SML-7002) was $20, the System Monitor Reference Manual (SML-7003) was $25, and the Hardware Reference Manual (SML-7004) cost $20. In Japan, the prices were higher ($13, $28, $33, $43, and $37). While the prices may seem high, Sony was widely praised for the quality of their documentation, with the extensive documentation touted in the press as a reason to consider buying the system in the first place

In the US, the manuals came in a 3-ring binder, and each manual included a disk holder to store the master copy of the software. The manual model numbers ended with a Z to indicate they included the binder (e.g., SML-7002Z; you’ll notice in the picture that some of the manuals reference the part number of the software, while others have the part number of the manual). You might also be noticing as you read that almost everything for this system has a part number, and almost all of them start with SM (Sony Micro), followed by another letter. For example, SML stood for literature (though it wasn’t consistently used, many manuals used the same part number as the underlying software), SMI for interface unit, SMW for software, SMD likely for device, SMK likely standing for konpyūtaakusesari, the Japanese word for computer accessory, or kēburu the Japanese word for cable; K was used for all of the cables and a couple of accessories, including the monitor stand and expansion module cases). SMF was also used for all 500 series cables (SMF-500 to 506).

There was also an SMC-70K that was released in Japan, there is no information about the K stood for in this context. The serial number range for this variant appears to begin at 60,000, while both the SMC-70 and the SMC-70G both began at 10,000. It is possible the K stood for kana, as the system’s keyboard had a JIS X 6002 standard kana layout, whereas the Japanese SMC-70 and SMC-70G both followed the Gojūon (fifty sounds) kana layout, which is roughly analogous to alphabetical order. Both keyboards had 73 keys, one more than western keyboards (a kana lock key next to the help key).

Other identifiers included SMJ-E for Japanese educational software, SMJ-G for Japanese game, SMJ-S for Japanese software, SMW-E for software educational, and SMW-G for software game. SMW-H also existed for software home & hobby, but software under this category appears to have been released only for the SMC-777.

Sony’s model, release, and versioning scheme wasn’t always exactly clear. For example, Metasoft’s Letterwriter was SMW-7045, but this wasn’t noted on the disks. The disk is labeled as version 1-A. The title screen indicated it was LetterWriter 2.0. For part numbers, an A meant it was the second release of a product (e.g., the SMI-7011A was the internal floppy drive expansion that was populated with only one drive, but it was the second revision that included the ability to work with auto shutter disks). But for software, version 1-A was the first release, and 1-B was the second. This did not apply to games released in Japan, which ended in D (for disk), though C is the furthest software revision I have seen. D was used on a software release, Graphics Editor, which meant that version supported a digitizer. K and L were only used once to distinguish two different software titles with the otherwise same part number (SMW-7040K, Sony Japanese Word Processor and SMW-7040L Sony EZ Report). Both programs are nearly identical. Lastly, P and PE were sometimes used as prefixes and suffixes for PAL systems, such as for Q-Manager (SMW-P7076), Video Titler (SMW-PE7070), and the PAL Superimposer (SMI-7074P).

The Word Processor had at least 3 releases, with SMW-70461-B being version 1-B but listed as Word Processor 3.0K, and SMW-70461-C being version 1-C but listed as Word Processor 3.0M, yet the W/P Mathpack had 2 releases, with SMW-7049 version 1-A being listed as W/P Mathpack Ver 3.0K, and SMW-7049 version 1-B listed as W/P Mathpack Ver 3.0M.

The computer (and software) didn’t come with a copy of the CP/M operating system. CP/M 2.2 Release 1.0 was released for the system (SMW-7002) and retailed for $150. Known versions include releases 1.0, 1.0J, 1.1, 1.1J, 1.2J, 1.2GP, 2.0, and 2.1 (while I would think there should be a 2.0J version, oddly I haven’t seen evidence of one, nor a 2.0 PAL version). Version 1.2 is the first version with support for the SMC-70G. Without a copy of CP/M, it’s not possible to do anything with software disks. One of the first instructions in any software manual was to make a copy of the disk, and make that copy bootable using a copy of CP/M. Because of the price of software, Sony never wanted users to work with the original copies!

Some programs offered their own installation utility, and Sony recommended keeping the application on one disk and files on another. Here is a short video of the drives in action installing SSG’s General Ledger:

The 3.5″ floppy drives that were available as an option on the SMC-70 were what set it apart from other systems on the market. The development of the 3.5″ floppy drive by Sony began in late 1979, but it’s not quite the same floppy drive that was widely used in computers around the world. In some ways, Sony’s was both better and worse. Sony’s drive had the same transfer rate as a double density 8″ drive at 500 kbps, making it have twice the transfer speed of both 5.25″ and modern 3.5″ drives. It did this by spinning at 600 RPM, twice the speed of a standard 3.5″ floppy drive. One of the side effects of this high rotational speed was a lower latency of 50ms compared to 100ms of a typical 3.5″ or 5.25″ floppy drive. Prior to the release of Sony’s drive, 5.25″ drives had a transfer rate of 250 kbps; and this is ultimately the reason today’s floppy drives spin at 300 RPM. The industry wanted future 3.5″ drives to be backwards compatible with existing 5.25″ drive controllers so they didn’t have to create new hardware. There were a few other differences as well. One major one that impacted compatibility between Sony’s existing 3.5″ media at the time and newer drives was the coercivity or magnetic strength with which the data is written to the disk.

Sony’s original disks stored data using a lower coercivity magnetic coating (one source says 500 oersteds (though another says it was 580 oe, and other 550 oe, the same as Betamax) that’s 2.54 microns thick), and therefore modern drive heads can’t read the media; the magnetic field is too weak (they store data using a disk magnetic coating with 650-665 oersteds for double density disks (the MIC compromise was 625 oe), and 720-750 oe for high density (1.44MB) disks that’s 2 (for DD) or 1.2 (for HD) microns thick). Another major difference was the media used 70 tracks instead of 80, which gave the disks an unformatted capacity of 437.5K, and 280K formatted (the formatted capacity depending on the file/operating system). The original drives were single sided. With each track storing 6.25K, 80 tracks would provide 500K of storage per side, or 1MB per disk, which was what eventually became the standard. It’s possible to replace an existing drive in the system with either the Sony OA-D32V or OA-D32W, and with a modified version of CP/M, the SMC-70 could access all 80 tracks on a disk.

Releases 2.0 and 2.1 of Sony’s CP/M partially supported the doubled-sided drive as well, but the support was half-baked. The backup utility would format tracks 0-69 on side one, and then tracks 0-69 on side 2, but it would fail to sysgen (install the bootloader), not could it do the track-to-track backup of a disk. If using the newer drives to only read files, a consequence of this modification would be the newer drives cannot read manual shutter media with the weaker magnetic field.

For anyone who wants to archive Sony disks that are on manual shutter disks, the best way to do it is to copy the disk to an auto shutter disk, and then archive this disk. Sony’s backup utility will make a track-by-track copy of the original disk.

The final difference between Sony’s standard and modern disks was that Sony did not include an auto shutter, or spring-loaded disk shutter. On the original Sony disk, the OM-D3310 (Office Media), the user was required to manually open the disk shutter before inserting the floppy disk into the drive. After ejecting the disk, the shutter had to be manually closed.

The first product to use the newly developed 3.5″ drive was Sony’s WYSISYG word processor announced in December 1980 and released in 1981, the Series 35 (OA-S3300, OA standing for Office Automation). The news of the floppy drive was a bigger deal than the word processor! Their second product to use the drives was the SMC-70. The SMC-70 optionally shipped with the SMI-7011 or SMI-7012, which was an expansion unit that housed either one or two model OA-D30V drives (single sided), at a price of $650 for a single drive and $1,200 for two. The unit included the floppy drive controller, which was installed inside the unit, and used one of the two available expansion slots. The floppy drive expansion contained the system’s only fan. There was an external floppy drive expansion that also allowed for up to two additional 3.5″ drives to be installed (SMI-7013) at a price of $725; it included a single drive. This was an incredibly rare accessory, as there wasn’t much of a reason for someone to have more than two floppy drives connected to a single system. Note that 5.25″ and 8″ drives could not be connected to the 3.5″ floppy controller, there was another accessory for connecting those drives. The price for a bare drive (SMI-7014) itself was $500, which could be added as a second drive to the SMI-7011 or the forth drive to the SMI-7013. A short time later the SMI-7011A/7012A/7013A/7014A started shipping, which changed the drive to a model OA-D31V/MFD-31V drive. This drive included the ability to open the disk shutter.

When Sony decided to sell their drives to others, it was thought that they would face an uphill battle with the 3.5″ drive. For starters, internally, Sony’s policy was that they did not sell their products to OEMs, so the only place for a Sony drive would be a Sony device. Next was there were a number of competing ~3″ floppy standards being introduced (though Sony’s was the first), some by established companies, and at the time Sony was not a manufacturer of 5.25″ or 8″ floppy drives, nor were they in the computer business. But Sony was quite familiar with magnetic media, as they were a leader in broadcasting, which was what led them to create the drive in the first place. By September 1983 an estimated 50,000 3.5″ drives had been sold, 25,000 of them by HP. Sony’s offering was also superior in many ways to both existing formats and the new formats that were popping up. Perhaps their most important advantage in the ~3″ battle was storage capacity.

Software was shipped on both manual and auto shutter media, and as mentioned, Sony was quick to release a drive that supported this new auto-shutter design, and they offered retrofit kits for existing drives, making manual shutter drives somewhat rare to find. Drives with the mechanism to open the shutter often say “Auto Shutter” on them, unless the retrofit was installed. This labeling was unique to Sony, other manufacturers used blank drive face plates. Sony also had a little indent above the drive in-use LED for a sticker to indicate the drive letter that other manufactures did not include.

Sony had to make media with a locking shutter for some time to be backwards compatible with drives that did not have the retrofit applied, though only the OA-D30V and OA-D31V could read the first generation of media (OM-D3310) as mentioned above. Because the auto shutter media (OM-D3320) had the locking shutter, many users thought they had to manually lock the shutter before inserting it into the drive, negating the entire purpose of the auto shutter! It could have been out of habit because they had to do it for some disks, so they did it with all disks. Disks were sold in 10 packs at a price of $5 per disk ($17.86 a MB), which is around $17 a disk today, and $68 a MB.

Being this cutting edge wasn’t necessarily a good thing; while history shows Sony was the victor in the floppy format war, this wasn’t assured, and we know they didn’t have as much luck with Betamax, Memory Stick, and MiniDisc (though MiniDisc was popular in Japan). But this history of creating media formats was what got Sony into the computer business in the first place. While so much of their system was cutting edge, one thing that really stood out in 1982 as not being terribly cutting edge was their reliance on CP/M.

Sony debuted the computer at the June 7th National Computer Conference in Houston Texas in 1982. Like IBM a year earlier, the industry was expecting Sony to enter the market. The industry was just expecting them to enter the market with a 16-bit computer. What was hyped at the launch was that the system would interface with video disk readers (and recorders) when commercially available, but details were scarce.

The technical documentation of the SMC-70 was nearly finalized by July of 1982. In a typo-ridden preliminary technical training manual published that month, the company left blank the power supply wattage in a specifications section, but a picture of a prototype unit showed a 60-watt power supply (production units have a 114-watt power supply, though just 65 watts is available for peripherals, a number shown on the rear of Japanese systems, but not those released in western markets, which show voltage and amps) and the 50-pin rear I/O expansion had an IDC connector, not a Centronics connector). The system was also labeled as a personal computer on both the rear label and above the keyboard, which Sony later changed to Micro Computer.

For anyone keeping track, the running total for a PC with monitor, monitor cable, disk drives, operating system, manuals, and a pack of disks would run $3,760. A dot matrix printer, cable, and monitor stand (SMI-7020; $800, SMK-0020; $60 & SMK-0091A or SMK-0091B; $60) would bring the total to $4,680. This was a competitive price. The IBM PC cost $4,540 for a system with the same 64KB of RAM, a single 5.25″ floppy drive, a CGA card with CGA monitor, and PC-DOS. The Sony included a real-time clock with battery backup (which incidentally, the original NiCad batteries still work on all of my systems, though like most systems of the era, the clock is not Y2K compliant). Both offered options to expand their respective systems, though Sony’s method was much easier.

The SMC-70 had 2 internal expansion ports, 3 external expansion slots, and a rear port to allow additional expansion options, including an expansion unit, the SMI-7040 ($575) that provided 5 more slots. Since the video, serial, and parallel ports were built into the SMC-70, they did not tie up expansion ports like those options did on the IBM 5150.

• 1. Internal expansion ports
• 2. Sharp Z80 processor
• 3. 2 128kbit (16KB) system ROM chips
• 4. RTC battery
• 5. Spare power connector
• 6. 50-pin expansion for 192K Bank RAM (SMI-7051)
• 7. 19,200 baud serial adapter

One internal expansion port was almost always used for the 3.5″ disk controller. The second could be used for a variety of upgrades. In the US, another, though extremely rare upgrade could be the 192K bank RAM card, which would increase the total RAM to 254K.

The second use for the other internal slot was the various kanji character ROMs in Japanese and Chinese systems. The interface card to support these was standard on the Chinese and Japanese variants of the SMC-70 (the SMC-70 was launched in Japan 3 months after the US launch). Western market SMC-70/G units had 2 16K ROM chips on the motherboard that included System Monitor and Sony BASIC. Asian market systems needed to support basic kanji characters, and there wasn’t enough free space in ROM to do this, so a daughterboard (shown below) was added that tied up one of the two expansion slots (the disk controller typically used the second available slot), the system ROM was recompiled into a single 16K ROM and kept on the motherboard, and then System Monitor, Sony BASIC, and the expanded character set were stored on two additional 16K ROM chips on the expansion board.

The ROM card had 4 open sockets, which could accept the kanji ROM kit. The kanji ROM kit was comprised of four ROM chips (SMK-0052/SMI-7052; $174). It included around 3,000 16×16 dot characters (JIS level 1). As these weren’t for the US market (western market systems didn’t have the ROM card that permitted them to be installed), there’s not any US literature on them. Note that a Japanese system would not have room (an open expansion port) with floppy drives installed to install the bank RAM card, which I think speaks to its popularity!

The SMI-7054 ($785) and SMI-7055 (price unknown) were kanji ROM kits that occupied one of the external expansion slots. The SMI-7054 expansion card had 18 32K ROM chips, giving it over half a megabyte of storage (this is a picture of the external card, removed from the case)!

Both offered 7,445 higher resolution 24×24 dot characters (3,755 level 1, 3,008 level 2, and 682 foreign characters including English, Russian, Japanese, Greek, and Arabic numerals, while the SMI-7055 (Chinese Character ROM) included even more storage, and and contained both 16×16 dot (250K) and 24×24 dot (562.5K) characters.

Semi-External Expansion Options

Most users would use the external I/O expansion slots to expand the system. On the SMC-70 there were 3 available slots, the SMC-70G had 4. As you may notice in the picture of the internal and external PCBs, they look similar. Sony made it so it was possible to remove an external card from its case and install it internally in the system. This wasn’t useful with most cards, since they required a way to connect to an external device. But a few, like the ROM cards and disk cache card did not need any external connections.

With the external expansion unit that plugged into the rear of the unit (SMI-7040; $575), it was possible to add 5 more expansion slots, at the cost of added latency for any devices using those slots. The SMC-70 shipped with no expansion options installed, but the SMC-70G shipped with a superimposer, so the expansion bus cannot be completely collapsed if all of the expansion cards are removed (at least one card should be installed). The NTSC superimposer takes up two spaces, while every other option (including the RGB superimposer) uses a single I/O slot.

Installing a new expansion module can be done in literally under a minute, and was revolutionary compared to anything else on the market. Each expansion module has 50 pins that plug into a 50-pin IDC connector on a ribbon cable. Two stainless steel centering pins guided the card into place. To install or remove a card, the user uses a coin or screwdriver to loosen two lock screws on the side of the unit, remove two large “knitting needles” (Sony called them fixing or guide pins) from the back of the unit, expand the system as much as necessary to accommodate the new module, snap the module into place, compress the system together, reinsert the pins, and tighten the screws.

When installing expansion boards, users were partially limited by available system power (2.4A@5V, 1.2A@12V, and 70mA@-12v). As an example, the 256K cache drives each used 400mA on the 5V rail, for a total of 1.2A. It would be okay to install 3 of them, except that the SMI-7012, the dual floppy drives, use 1,260mA@5V, and 1,090mA@12V, which would overload the 5V rail by 60mA. The SMI-7040 expansion unit had its own power supply with higher limits (3A@5V, 1.2A@12V, and 100mA@-12v). The SMC-70G’s power supply also was beefed up to deal with the additional expansion slots and the genlocking hardware, and could supply 3.4A@5V, 1.55A@12V, and 150mA@-12V.

D/SNY – Hard drive controller

Going down the list of expansion cards, the first is D/SNY, a Corvus hard disk controller, which is actually a third-party card created by Corvus for Sony. The card alone retailed for $300, and allowed for 3 different Corvus drives to be attached, 7MB, 14MB, and 21MB (before formatting). They were 1, 2, and 3 platter drives. On March 29th, 1983, the New York Times reported that Sony agreed to buy $13 million worth of drives and custom controller cards from Corvus for the SMC-70. Sony marketed the drives as 5.7MB, 12.1, and 18.4MB after formatting (though the CP/M manual referred to the drives as 5, 10, and 20 MB). For those with especially deep wallets, it was possible to connect multiple drives together.

The drives came with a utility to modify the BIOS of CP/M versions 1.0, and 1.1, and to configure the hard drive, though it was never possible to boot from the hard drive (if anyone has a copy of this utility disk, please reach out). Starting with Sony’s 1.2 release of CP/M it was possible to partition and format the drive directly within setup. Sony’s CP/M did not support partitions larger than 8MB, so the 20MB drive needed to be divided into at least 3 partitions. A drive could have a maximum of 7 partitions.

SMD-70

After the release of the SMC-777 in Japan, there was a massive release of games, also in Japan. The SMC-777 was functionally similar to the SMC-70 in many ways, which meant that almost all of the software on the SMC-70 would run on the SMC-777, but the SMC-777 had a PSG (programmable sound generator) and two controller ports.

While US SMC-70 systems had both ROM sockets occupied on the system board, in Japan, only one of the two sockets was used. Some users followed instructions in a magazine to create a so-called SMC-77 by putting the SMC-777 ROM in the open ROM socket, and running wires for a toggle switch outside of the computer to switch between ROMs. While the SMC-777 had a higher color palette, the only other things that were missing were the controller ports and the PSG. A company named SMD created an I/O module that contained two RJA jacks for audio (line out and audio in), a built-in speaker, and two controller ports.

Since the SMC-777 was never released in the US, this module was never released in the US. Even in Japan it is a relatively rare, as the SMC-70 wasn’t marketed as a home PC.

SMI-7016 – 8-inch FDD control unit

At launch, the 8″ floppy controller for the SMC-70 only supported single-sided, single-density 8″ floppy disks, though this was a software limitation. It was marketed that the SMI-7016 would be a general floppy disk controller, and would work with both 3.5″ and 8″ floppy disks, but this didn’t match reality. Sony themselves never sold an 8″ floppy drive, and the controller did not support Sony’s 3.5″ drives. The controller has a 37-pin female DB connector, but that connects to a 34-pin connector internally on the PCB, though at one point in marketing materials the connector was a 34-pin male IDC connector with locking tabs. CCC (Computer Curriculum Corporation), which sold courseware to schools throughout the 70s and 80s, sold a branded version of the card. CCC sold complete Sony systems with 8″ drives and CCC’s educational software. In Japan there is another variant of a floppy disk controller that uses a Centronics connector that has BUG branding on it, the company responsible for Sony’s Disk BASIC.

As time went on, Sony’s CP/M included support for additional 8″ formats (SSDD, DSDD), along with 40- and 80-track 5.25″ disks. It was possible to boot the computer from this controller card, but it wasn’t possible to swap between booting from an 8″ drive to a 3.5″ drive. According to Sony, if an 8″ drive is set as the system (boot) drive, a Sony 3.5″ drive cannot be physically installed in the system. If booting from a 3.5″ drive both drives can co-exist.

Sony’s CP/M supported drive letters A through P, but according to Sony, it did not support 16 physical drives. According to the CP/M Operating System manual, if using 3.5″ floppy drives, a 3.5″ drive must always be drive A, a maximum of four 3.5″ drives, four cache drives, and two 8″ drives can be installed, with no more than 8 drives total supported. The SMI-7016 disk controller supports a maximum of 4 drives. This may not be accurate though, it seems the real limitation is no more than 4 physical disks of any type, with a maximum of 16 total logical and physical drives.

SMI-7031 – RS-232C / SMI-7031A – RS-232C Programmable

The SMC-70 shipped with an internal serial port, and it was possible to add up to two more via these expansion cards. There were two version of this module that sold, The SMI-7031 for $175 and the SMI-7031A for $300 (a difference of around $430 today), so you can guess which version was more popular in the market! Opting for the programmable model meant a program like Softcom could adjust the baud rate of the card (110, 300, 600, 1,200, 2,400, 4,800, 9,600, or 19,200 baud), otherwise it had to be adjusted via switches on the card, which involved removing it from the computer.

Both the onboard and the SMI-7031 RS-232C ports were controlled by a 8251A USART chip. On the SMI-7031 there were two push switches for signal direction (pushing one caused the other to pop up, and vice-versa), a 9-switch block with 8 switches for setting the baud rate, and one for setting the card’s address. Three more individual switches control the receive and transmit clocks (internal or external) and set the card to synchronous or asynchronous mode.

The onboard RS-232 interface shows that the 110 baud setting is for 75 baud as well (set via a switch block); the internal port cannot be set to synchronous or asynchronous mode. The internal RS-232C port has a single switch for selecting the direction of the communication (to terminal, or to computer).

SMI-7032 – IEEE-488 / GPIB interface unit

Looking at Sony’s marketing materials, it’s evident they intended the SMI-7032 to allow the SMC-70 to be used in scientific settings. The interface was originally called HP-IB, as it was invented by HP, so perhaps it’s ironic that HP was using the interface to connect Sony’s 3.5″ disk drives (via the 9121 expansion) to computers such as the HP 150. Aside from an IEEE-488 cable (SMK-0032; $94), Sony didn’t specifically market IEEE-488 accessories for the $300 card, but a few products they made contained the port, including oscilloscopes and waveform generators. The picture below shows the SMC-70 controlling a Anritsu MS420B Network Spectrum Analyzer. BASIC and ROM BASIC did not have native support for the SMI-7032; support was extended by linking IEEE488.PAC (PAC standing for ROM pack) during program execution, which was included in ROM in the SMI-7032. An updated IEEE488.PAC file was included with every copy of Disk BASIC, and users were instructed to use not use the version in ROM when using Disk BASIC.

GPIB ports were options on most 80s PCs, from the Apple Macintosh and Commodore 64 to the IBM PC and compatibles, but were always fairly rare. Even today it’s possible to get a USB to GPIB adapter for $60 to support existing equipment. In a way, the standard reminds me of Firewire and USB 1.1. Compared to serial, GPIB offered much faster speeds, up to 1 MB/s, and (depending on the platform) users could connect up to 31 logical devices. Being a parallel bus, more wires are used to transmit data compared to serial, though in the US Sony charged the same price for their RS-232C cable, despite it only having 13 conductors, while GPIB has 24.

SMI-7040 – Expansion Unit

As previously mentioned, the SMC-70 had 3 external expansion slots, while the SMC-70G had 4.  A user could quickly run out of space to expand the system.  There were two solutions to this; one from Sony was a 5-port expansion unit that sold for $575.  Because it had its own power supply, users didn’t have to worry about overloading the main unit.  Because the power supplies are isolated, the battery backup (SMI-7080) module can’t power the SMC-70 when installed in the expansion unit, though since I don’t have the battery backup module, I don’t know if it would keep the expansion unit running in the event of a power failure.  This would be important if a user had a cache disk unit (SMI-7050) installed in the expansion unit.

The expansion unit is fully buffered, which means there added latency when transferring data to and from modules installed in the unit compared to modules installed directly in the system, though in practice the impact is negligible.  For example, transferring 256KB of data between 2 cache disks installed internally averaged 17.8 seconds, 2 cache disks externally, 17.8 seconds, and 18.2 seconds with 1 cache disk installed internally and 1 externally.   

The unit works similarly to main computer.  Two screws on the side are slightly loosened, the guide pins are removed, and the front can be extended to accept 1 to 5 modules.  The modules fit back to front, instead of front to back.  After a module is inserted, the pins are replaced and the screws are tightened. 

One downside to the expansion unit is it’s not possible to daisy chain the Videotizer (SMI-7075/P) or Supercharger (SMC-7086) off of it, so users have to decide which of the three external options they wish to use.

BUG Accessories

In Japan, the company BUG also released a number of quite unique expansion modules, most of which I have never even heard of, let alone seen outside of an advertisement in the March 1983 issue of ASCII magazine.

What was unique about these cards is they came with the option of buying just the bare board for ¥7,000 less than a card with the case. BUG also sold an expansion unit that could hold cards without cases for ¥89,000 (the official Sony expansion unit held 5 with cases and sold for ¥138,000). If a user needed 8 cards, by getting the expansion unit without cases it effectively reduced the cost of the expansion unit to ¥33,000. The BUG modules in the list are:

• 8-inch floppy drive controller: double-sided high-density floppy disk controller; supports up to four NEC FD1165AV drives
• 9-voice music sythesiszer(sic): enables sound and music generation via LINK command from BASIC. Includes Screen Music Editor to allow composition and playback with a 5-line staff display.
• 8 bits A/D · D/A · PIO: 8-channel 8-bit A/D converter (conversion time: 100 µsec, input voltage: ±5V, 2-channel 8-bit D/A converter (output voltage: ±5V), 16-bit input / 16-bit output PIO; includes interrupt timer and control subroutine ROM and supports control directly from BASIC
• 12 bits D/A Converter: 4-channel 12-bit D/A converter (output voltage: ±5V); includes programmable timer and control subroutine ROM. Supports control directly from BASIC
• 12 bits A/D Converter: 16-channel 12-bit A/D converter (conversion time: 26 µsec, input voltage: ±5V); Includes programmable timer and control subroutine ROM. Supports control directly from BASIC
• Isolated I/O: 6 channel inputs, 10 mA; 24 channel outputs: 40V, 35mA. Supports control directly from BASIC
• 8 channels Relay: 8-channel SSR output (zero cross, 150V 1A), 8-channel on/off input with chattering cancel feature. Supports control directly from BASIC
• Universal Box: Free space for sixteen 16-pin ICs, includes bus connector header, 50-pin cable connector, ROM pack, address decoder section (unpopulated)

They also listed some general equipment here:

• 8 inches Floppy Disk Unit (8FDD): Equipped with two 8-inch double-sided high-density floppy drives (NEC FD1165AV). Includes metal case (uses 8FDC controller, sold separately)
• 8 Slots Expansion Box (EXBX): 8-slot expansion box, accepts up to 8 peripheral cards (without boxes). Includes bus buffer and power supply.

While outside the scope of this section, they also listed software they wrote, PC2SMC (PC8001 to SMC-70 converter on cassette), SMCLIB, FORTRAN-80 + SMCLIB (3.5″ or 8″), BASIC-80 Compiler + SMCLIB (3.5″ or 8″), MACRO-80 + SMCLIB (3.5″ or 8″), S-BUG (Symbolic Debugger).

…to be continued!

Technical Reference

RGB Multi Input Connector Pinout

Here is the pinout of the RGB multi-input connector used on the KX monitors:

Here is a more complete pinout:

34-pin RGB connector:
01 = +5V             18 = no connection
02 = +5V             19 = no connection
03 = ground          20 = Audio, Right
04 = ground          21 = Mode Switch (digital RGB vs analog RGB)
05 = Remote Ctl gnd  22 = no connection
06 = Composite gnd   23 = Video (composite)
07 = Audio ground    24 = Audio, Left
08 = Red ground      25 = Red
09 = Green ground    26 = Green
10 = Blue ground     27 = Blue
11 = Ground          28 = no connection
12 = Blank ground    29 = Blanking
13 = Hsync ground    30 = H-sync
14 = no connection   31 = V-sync
15 = Vsync ground    32 = no connection
16 = Ground          33 = RGB vs Normal
17 = no connection   34 = Audio Select (+5v enables audio)

RGB to PVM Pinout

Pinout of the SMK-0002 cable for the PVM series of monitors.

Here is the pinout of the RGB connector on the computer:

B/W Multi Out Pinout

This is the B/W multi out pinout used to connect the SMC-70/G to the CPD-120 monochrome monitor:

Pin 1 - H. Sync
Pin 2 - V. Sync
Pin 3 - Sound Out
Pin 4 - 625 / 525
Pin 5 - Ground
Pin 6 - Ground
Pin 7 - Ground
Pin 8 - B/W Video

Recreating Disk Labels

If you’d like to recreate disk labels, it appears Sony used Swis721 Md BT bold (size 19) for the title, subtitle (14.5), Swis721 Md BT for MICRO COMPUTER (8), Swis721 BlkOul BT (16) for the SMC-70, and Swis721 BT (8) for the text on the bottom of the label:

Creating and Restoring Disk Images

To make and restore an image of an existing IMD floppy images, I suggest using a program called ImageDisk. You can use any computer running DOS to run the utility, but running it under Windows 98 is convenient because you can then copy the files over to a USB flash drive. As noted in the main article, this utility cannot back up manual shutter disks, because modern floppy drives cannot read the weaker magnetic field on these disks. The workaround is to use Sony’s backup utility to make a track-to-track backup of the disk on the system to a non-manual shutter disk, and then archive that disk. You can follow these directions:

If in Windows, open a command prompt
Navigate to where IMD is saved on your hard drive
Type IMD, press Enter
Press Escape
Press S
Arrow down to Sides, press space once to change it to single (optional)
Arrow down Double-step, press space once to change it to off (optional, unless writing a disk)
Arrow down to 500 kbps, press space twice to change it to 250 kbps
Press Escape
Press R to read disk, or W to write a disk
If reading, enter a short name for the disk (8 or fewer chars) and press enter
Press Escape (you can also optionally enter a description)
Press Enter
Press Enter after complete

Press R to read the next disk

22DISK

22DISK is a DOS-based utility that allows DOS to interact with CP/M disks. With it, it’s possible to format a disk, display the contents of a disk, display the contents of files, erase files, and copy files to and from a disk. 22DISK does not come with a profile for the SMC-70 file format, so one needs to be added. The profile to add is:

BEGIN SON1  Sony SMC-70 - SSDD 3.5"
DENSITY MFM, LOW
CYLINDERS 70 SIDES 1 SECTORS 16,256
SIDE1 0 1,4,7,10,13,16,3,6,9,12,15,2,5,8,11,14
BSH 4 BLM 15 EXM 1 DSM 135 DRM 127 AL0 0C0H AL1 0 OFS 2
END

CPMTOOLS Definition

CPMTOOLS is Linux-based utility for working with CP/M disks. Like 22DISK, you can use it copy files back and forth from a floppy disk, view the files on a disk, erase files, as well as some additional file system functionality. Here is a diskdef you can use:

# Sony SMC-70 3.5" SSDD
diskdef smc70
  seclen 256
  tracks 70
  sectrk 16
  blocksize 2048
  maxdir 128
  skew 3
  boottrk 2
  os 2.2
end

FlashFloppy Definition and External Drive to Gotek Pinout

If you’d like to connect a Gotek to the SMC-70/G as an external 3.5″ drive, here are the FlashFloppy parameters:

# Sony SMC-70
[::286720]
cyls = 70
heads = 1
id = 1
interleave = 1
secs = 16
bps = 256
mode = mfm
rate = 500
rpm = 600

Here is the pinout:

DB25F to 34-pin female IDC for connector of Gotek emulator mapping

IDC-34 pin                  DB-25M pin

8        Index*             9
10       Select 0*          1
12       Select 1*          2
16       Motor On*          14 (Not used by Gotek/FF)
18       Step Direction     3
20       Step*              4
22       Write Data*        5
24       Write Gate*        6
26       Track 0*           10
28       Write Protect*     11
30       Read Data*         12
32       Side Select        8 (Not supported by stock BIOS)
34       Ready              13

Odd Pins GND                15-19, 21-25

Also to be continued!

Known Hardware, Software, and Accessories

Like the rest of this page, this is a work in progress!

Systems

Monitors

Expansion Modules

If you happen to be looking to get rid of any hardware, especially the SMD-70 (PSG board), SMI-7013 (external drive expansion), SMI-7051 (192K bank RAM), a kanji ROM card, or SMI-7080 (battery backup), please let me know!

Software

If you have any software for the SMC-70/G, please reach out! This list is pieced together from many difference sources over the years, including press releases, marketing materials, magazines, product inserts, and software catalogs.

Media

Accessories

If you have any accessories to offload, please reach out! I am keeping an eye out for the XEBEC-70, SMD-7140 (carrying case), and SMK-0032 (IEEE-488 cable).

Literature

Some operating instructions and service manuals did not have traditional part numbers, and are instead listed by the number assigned by Sony.

Japanese/Games

Much of this software was released after the SMC-777 was released, and just happens to also be compatible with the SMC-70/G. Because of the overlap of the systems, I haven’t removed the SMC-777 software from this list, but as I test available software I will make a separate SMC-777 list if it does not run on the SMC-70/G.

Nearly everything (if not everything) on the games list was published in Japan, so the translations of the titles may not be exact.

Resources

Software

Release 2.1 is the final version of CP/M released for the SMC-70. The files on a factory disk are:

ASM.COM
BACKUP.COM
DDT.COM
DIAG.COM
DUMP.ASM
DUMP.COM
ED.COM
LOAD.COM
PIP.COM
SAMPLE.TXT
SETUP.COM
STAT.COM
SUBMIT.COM
XSUB.COM

There are two known releases of Sony’s Video Titler, Release 1-A, which is version 1.0, and version 1.1 (which logically should be 1-B). I don’t have the original disks for 1.1 to confirm if this is the case. If anyone has a scan of version 1.1 to share, reach out!

Sony did not release a specific release of Wordstar, but this version was configured for the SMC-70. There’s no need to run the installation program, it’s ready to go.

Literature

SMC-70G supplement to the SMC-70 operating instructions.

SMC-70 Service Manual ( 600 DPI scan), printed March 1983.

Sony Video Titler (SMW-7070) 3-773-637-21(1) Software Manual

System Monitor and Hardware Reference Chart 3-795-473-21 (2), printed 1982