Date: Tue, 27 Nov 2007 10:52:00 -0800 (PST)
From: Fred Cisin <cisin at xenosoft.com>
Subject: Re: Teaching kids about computers...
>> So, I propose that programming be taught first in machine language,
>> then assembly. That's how I learned to do it.
>EAM first! There's nothing like "cardboard technology" to demystify the
>whole thing. "How can you use an 08x sorter (one column at a time) to
>efficiently arrange a large deck of cards with a sequence number in 73
>through 80?" "Wire a plug board for an interpreter to print last name,
>then first name, that have fields in the middle of the card, flush left."
>"Use a 407? accounting machine to print results directly onto a form
>1040." "Use a Gerber Data Digitizer ("Etch-a-sketch") to make a deck of
>cards with a risque picture."
>OK, NOW write machine language. (1401 emulator on a 1620)?
------
RIGHT ON!
That's how I got started, and it's definitely the only way!
The noise alone will be special, not to mention the excitement when little
brother trips him/her on the way from the sorter to the collator and 4000
cards go flying across the room; what better way to grasp the concept
of a glitch on a data bus...
But I didn't have anything as modern as a 407; In My Day we only had 402s!!!
BTW, my claim to fame was making it multiply; they said it couldn't be done, so...
Haven't seen any with peripherals on eBay lately though...
m
> You are at a dead end of a dirt road. The road goes to the east.
> In the distance you can see that it will eventually fork off.
> The trees here are very tall royal palms, and they are
> spaced equidistant from each other.
> There is a shovel here.
>
> Forget the shovel ... I want to see the babes under the palm
> trees. :) BTW I wonder why I never can win at these games.
Wrong game dude, you want Leisure Suit Larry!
James -
"All lies and jest, still the man hears what he wants to hear and
disregards the rest"
Hi,
> And that's exactly why I think it's a poor choice. You can't
>_really_ understnad what goes on inside those blocks....
But you don't need to when you're starting out.
Why get bogged down with the intricasies of a board full of TTL when all you
need to know is how to drive it?
I suppose what I'm saying is you need to keep things fairly simple to start
with (but not *TOO* simple). Getting the balance right is tricky....
TTFN - Pete.
Hi,
>>....the Beeb is a fairly formidable system to understand....
> Is it? Why? Are you talking abotu understanding how to program it, or
>understanding the hardware?
The hardware.
It's a very clever design, but looking at it from the point of view of
someone who's just learning about computer electronics, I think it would
look pretty daunting. The 64 is a much simpler system.
I think the Beeb would make an ideal SECOND system once they've got "the
bug".
>....has 64K*4 RAM, which is fiddled by the ULA to look like 32K*8
>to the processor. I am not joking.
I'd forgotten about that....did anyone ever figure out how much of a
performance hit the machine took because of that?
TTFN - Pete.
Hi,
> Oh I don't know. If you hate PCs so much....
Quite honestly, the *ONLY* reason I use PC's is because of the availability
of software (and the speed obviously). If it wasn't for that I'd probably
still be running my old MegaST.
>....you should have designed your own motherboard, so you
>could haevve done things properly...
....but if I'd done that I'd have used a 68K instead of that Intel garbage
IBM chose.... ;-)
TTFN - Pete.
> How much of a difference is there between the two, really?
The big difference is the addition of bus disconnect/reconnect in SCSI.
SASI devices hogged the bus until a transaction completed, which didn't
work well for high latency operations like tape seeks/rewinds.
An NCR 5380 SCSI controller will work fine with SASI devices. At one
point it was easy to find them on ISA cards, haven't looked lately.
Mixing SASI/SCSI on the same bus is problematic if the SCSI devices try to
disconnect.
Message: 10
Date: Thu, 22 Nov 2007 12:17:31 -0800 (PST)
From: Fred Cisin <cisin at xenosoft.com>
Subject: Re: FD400 drive troubleshooting
>Many/most drives have 50Hz/60Hz zebra discs on the flywheel, for using a
>flickering fluorescent light.
Which just happens to be the ratio of 300RPM vs 360RPM, so that on a 300RPM
strobe disk w/a 60Hz light the 60Hz bars = 300RPM and the 50Hz bars = 360RPM.
FWIW,
m
> From: rtellason at verizon.net
>
>
> I notice that even those guys that are building relay computers "cheat" and
> use a single small solid-state chip for RAM. :-)
>
Hi
I've been thinking about how one could make a reasonable
memory, using small reed relays. If one puts a magnet close
to one end, it will cause the reed to close. Move it back
some and it will hold until the field is too weak.
If one set the magnet someplace in the middle of this
band, one could use the direction of current through the
coil to set and reset the contacts.
One could create an array of these for the memory. Placing
small magnets in opposite directions for adjacent bits would
keep from building too high a field buildup, in the array.
I was thinking that one could use small round magnets
glued to the end of a threaded rod. This could then be adjusted
to optimize the memory.
Now all I need is a pile of reed relays.
Dwight
_________________________________________________________________
Put your friends on the big screen with Windows Vista? + Windows Live?.
http://www.microsoft.com/windows/shop/specialoffers.mspx?ocid=TXT_TAGLM_CPC…
(Since no-one seemed to notice this as a comment to an older thread...)
I recently got given a decent 21" colour monitor with a DB13W3
connector on it. Never used one of these before.
In the same pile of stuff was a Mac video connector to DB13 cable.
I've tried this on an old Beige G3, and also via an SVGA-Mac convertor
on a PC. It gives a good sharp picture, but on both systems, red and
green were reversed.
Does this mean my cable's incorrectly wired up or doesn't belong to
this monitor, or is that something to do with using a DB13 monitor on
a modern PC?
--
Liam Proven ? Profile: http://www.linkedin.com/in/liamproven
Email: lproven at cix.co.uk ? GMail/GoogleTalk/Orkut: lproven at gmail.com
Tel: +44 20-8685-0498 ? Cell: +44 7939-087884 ? Fax: + 44 870-9151419
AOL/AIM/iChat: liamproven at aol.com ? MSN/Messenger: lproven at hotmail.com
Yahoo: liamproven at yahoo.co.uk ? Skype: liamproven ? ICQ: 73187508
At 11:46 PM 11/26/2007, Rod Smallwood wrote:
> I'm sure that I heard that some Commodore systems could do TV out
>and were in fact used to produce CGI stuff for 'Babylon Five"
>Does anybody know which ones and could they do PAL or just NTSC?
Special effects makers strove for higher quality as the job demanded.
Part of the appeal of the Amiga for special effects was the price
of the 32-bit hardware and software. SGI hardware and software
was an order of magnitude more expensive. NewTek's Lightwave was used
by the Babylon 5 special effects group. I know they also used
an early 3D Studio on a PC for some of the modeling. (And they
used some of my software to convert between 3D file formats; as I recall,
the spun shape of the original station was made that way.)
Yes, the Amiga had the horsepower to play back animations of
useful color depths in real-time. Depending on the image and
the requirements, some special effects might even look OK with
the straight TV-out. For example, the typical synthetic
"computer display" in a cheesy sci-fi show. When you're filming
an actor in front of an animation playing on a monitor, low-res is OK.
More often for serious output, as in Babylon 5's case, they laid
their bitmaps to an 8mm Exabyte tape as data files, then imported
into an Abekas framebuffer that could play them back in real time.
High quality, no generational loss every time you made an edit or copy.
Straight TV-out wasn't a high-quality method of exporting video,
though. In the early days, some people used single-frame video
recorders to lay down a sequence of animation. This worked
reasonably well, within NTSC generational limits. Later, some
NewTek Video Toaster-based animators used its higher-quality
framebuffer as the output to single-frame recordings.
- John
