I'd say there are multiple answers to this question, and they're all inter-related.
Definition/Utility:
In 1973 the definition of a "computer" wasn't what it is in common parlance today, IE, a user-friendly workstation optimized for live interactivity with a human being. That was in fact still the exception to the rule even if we're talking about "big" computers, let alone little ones. If you encountered a "computer" in a lab or industrial environment back then it was probably a PDP-8 with a front panel, and it may well be completely driven by said front panel most of the time if it's doing process control or whatever. The earliest microcomputers were generic "boxes of slots" precisely because the people who designed them didn't have any prescriptive idea of how customers were going to want to use them, and considering the cost of integrating an interactive terminal into the base model (next point) it would have been foolish to insist in 1974 that the minimum system include all this extra fluff that you certainly didn't need if your idea of what you wanted to use your Altair for was controlling pump relays in your chemistry lab.
Cost:
This has two parts, the cost of the terminals, and of the computers themselves.
I see in vintage periodicals ASR-33s being marketed to hobbyists at $1000+ each.. hardly cheap
First, yes, a "new" or professionally restored ASR-33 was in that ball park, but a surplus gray market one could be had for a lot less than that. (And you could go even cheaper if you were willing to deal with the hassle of using an ancient Baudot model.) This was still *much* cheaper than a "real" CRT terminal, which the TV Typewriter wasn't (I'll get back to this), and if you laid hands on a teletype with a paper tape puncher/reader then having it also solved the problem of program storage. If you add up the price of a dedicated CRT monitor (even if it's just a security monitor or a TV you're cutting the tuner out of), a cassette recorder, the interface board *for* that cassette recorder, and the TVT itself this is going to look like a lot more even comparison.
(Oh, you also get a printer with the ASR. Downside is you're having to use paper *all* the time, but win some, lose some.)
Robert Suding had a video card developed for the Mark-8 by late 74.
Sure, around the same time that the SWTP CT-1024 terminal kit was getting prepped for its debut in Radio-Electronics' January 1975 issue. Let's talk about both of those, along with the original 1973 TVT.
Hitting the 1973 TVT first, well, it wasn't a terminal, it was more of a proof of concept. It could be *turned into* a terminal, but it wasn't a "snap your fingers" affair, and the design of its memory system plus almost total lack of cursor controls make it only capable of pretty limited interaction. If you want an example of what a computer interfaced with the original TVT would be like look at the Apple I; this is *not* an endorsement. Is it better than a teletype machine? Well, it saves paper I guess? The big shift registers it used were already obsolete in 1973, which is why it was as "cheap" as it was to build, but building one up completely still was around $200, which is around $1300 in today's money. In January 1975 an Altair kit was $439, or $2500, so we'd be talking a 50% premium on the minimum investment to get started if it was built in, and... would it even be useful to have one of these on a base Altair? I guess this is another thing to get back to.
Next, well... I can't find much on Suding's board, but from what I can find it had a whopping 256 bytes of memory on it for a 32x8 display, and wasn't really a "video card", it was a TV Typewriter that had a Mark-8 compatible parallel interface port on the back of it that essentially inserted the Mark-8 between the screen and keyboard "loopback". (Note that this isn't a criticism of the design, it's just to make it clear that it's not a modern "video card" as we would think of it today.) From what I've been able to find about it access to screen memory was strictly serialized and the only "cursor control" it understood was "home"; characters looped in from top to bottom and you couldn't even backspace. Which, again, I guess makes it about the equivalent of an Apple I. I couldn't find a price for this board but based on the components used I'd likewise guess that by the time you were all in you'd also be in the $200+ ballpark?
The CT-1024 is probably the fairest direct comparison, and the timing was perfect for pairing it with the Altair, since they came out almost exactly the same time. (And it needs to be said that while the Altair got a reputation for not being a "great" experience to assemble the Mark-8 was apparently a nightmare to build even if you could find all the parts, with anecdotes claiming that the majority of attempts to build one never even worked.) The capabilities of the base CT-1024 were fairly similar to the Mark-8 board, other than it could hold four times as many characters in two pages. (The CT-1024 is usually thought of as a "serial" terminal, but it did also have the option of a parallel port interface, and fitted with that using it would be almost precisely like the Mark-8's board.) For a few more bucks you got better cursor control. The most commonly quoted price for a CT-1024
kit in "full terminal" configuration was $275 so... again, that pretty much is in the same ballpark at the other solutions.
So... let's pretend that the minimum increase in base price to ship an integrated CRT terminal (minus the monitor) in a computer at the kit level is going to be around $250 in January 1, 1975. I'm also going to grant that, sure, even a really brain-dead Apple-1 style slow and semi-serial display would be more "friendly" and productive to most people than the front panel. What does that translate to?
- It raises the introductory kit price of the Altair from $439 to $689, or in modern terms from around $2,500 to around $4,000. That's not chump change, and this is a cost that's going to come along with every computer sold.
- This jump in price is ignoring the fact that the base Altair only came with 256 *bytes* of RAM and had no PROM/EPROM socket for the machine language monitor you'd need to make this display run. Even if we say that leaving out the front panel and substituting a monitor PROM (like the later "turnkey" Altair) gives us a break even on that we're still realistically going to need more RAM for this to be practical. Looking at ads in the January 1975 issue of popular electronics a 1Kbit 2102 RAM chip was $16, making 1K worth of them a cool $128 right there.
- So now we're looking at a base price of at least $800 if we stick with static RAM. Or around $5,000 in today's money for the *base unit*. And we still have nowhere enough RAM or ROM to run a user friendly language like BASIC, this is all to give us a minimal machine language monitor instead of a front panel.
- You're still going to have to scrounge a CRT monitor somewhere, that's another hundred bucks or so, plus a cassette recorder (I'll pretend we worked the price of the interface for that into the terminal circuitry cost), so now we're at a thousand bucks in kit form... and you have to spend that all in one chunk. Ouch.
And again, at this phase are we really sure that's what we need a computer for? Who knows? Seems like maybe we need a few more monkeys banging on the typewriters before Shakespeare gets written; our $400 entry price already severely limits how many monkeys we can get to participate, is tripling the entry price right out of the gate the right move? And that leads to: (... next post)
