Can you do a compairsion of a 5.25" and a 3.5" disk (If you can get one if not don't worry)

Lots of pics on the net:

https://upload.wikimedia.org/wikipedia/commons/a/aa/Floppy_disk_2009_G1.jpg
https://upload.wikimedia.org/wikipedia/commons/d/df/Different_types_of_storage_components.jpg

Indeed, my picture doesn't do it justice - it looks way smaller than it actually is in real life. Holding one of these is so strange, and quite satisfying.

Many years ago, I saw a machine that used 8" floppies.  It wasn't a computer, and actually predated the original IBM PC.  It was an IBM Displaywriter.  It had 5 parts.  One box was its CPU.  A second box was a dual 8" floppy drive.  It had an IBM green screen monitor, similar to the one used with the PC or an IBM terminal.  It had a Final component was an IBM daisy wheel printer.  It would boot off one disc and store documents on the second.

I saw it at a yard sale.  They were thousands of dollars new in 1980 and I think the owner was still quite proud of it.  It was complete and in good shape, with all its books and discs.

Quote from: LampLover on November 27, 2015, 02:39:13 PM

Can you do a compairsion of a 5.25" and a 3.5" disk (If you can get one if not don't worry)

Lots of pics on the net:

https://upload.wikimedia.org/wikipedia/commons/a/aa/Floppy_disk_2009_G1.jpg
https://upload.wikimedia.org/wikipedia/commons/d/df/Different_types_of_storage_components.jpg

Indeed, my picture doesn't do it justice - it looks way smaller than it actually is in real life. Holding one of these is so strange, and quite satisfying.

Thanks, Trent
I did not think of it to search for a comparison picture the second one you posted is great
I can't believe how far technology has come now you can fit 128Gb on a MicroSD card that is smaller then your thumb (Also smaller then those USB "Thumb Drives" AKA the USB Flash Drive Lol!)

How much data did the 8" floppy disk store anyway?

@dor123
I have noticed that also that the 3.5" floppy was very unreliable at least to me during high school I almost lost a 10 page book report due to a bad disk (Luckily I saved it on my hard drive and I just copied it to the disk and not move it and then delete the original)
 
I bought a USB to Ethernet adapter to get an older first generation TiVo online and the diskette (A 3.5" floppy was unreadable, not that I or the Tivo needed it I was just curious to see what was on it) The adapter was New Old Stock

How much data did the 8" floppy disk store anyway?

There were several iterations from 80 KB to 1.2 MB in capacity. I think the one I posted is a 1.2 MB unit.

1.2 was the last 5.25" floppy capacity. Were really 8" floppies that high capacity as well ?

Yes, I looked it up before answering. Info is readily available on the Internet.

I received something awesome a couple of days ago. Someone who lives here who is also into vintage electronics found me on YouTube, and offered me a vintage computer that he didn't want anymore for free.

It's a Sharp PC-7000 portable PC from 1986. 7 MHz Intel 8086, 320K of RAM, two 5.25" floppy drives, and a monochrome CGA LCD display. The display has an electroluminescent backlight, and this was apparently the very first personal computer with such a display. Reviews touted this computer as having the highest quality, clearest LCD display of any computer at the time. Which is funny, because the display is absolutely horrible, by today's standards anyway. The contrast between lit pixels and unlit pixels is so poor that you're constantly straining to read it. Not because it was designed or implemented poorly - simply because the technology was in its infancy. Being able to make a working 10.5" LCD panel in 1986 was a feat in itself. With that said, if this was the best LCD display of the time, I wouldn't want to see the lesser ones. 

This is a pretty small computer. There are no expansion slots, so there is no provision to add a hard drive or any other expansion cards. You did get a decent selection of on-board I/O, though. In addition to parallel and serial ports, you could add an optional internal modem, CGA monitor interface, and a box which allowed you to plug in expansion cards. This unit was purchased with the modem, but sadly not the monitor interface, which would have REALLY come in handy with that display. lol

This unit works fine, but it does have a few minor issues. I accidentally discovered that there is probably a cold solder joint on the motherboard, as when you jostle the computer it does a hard reset. In addition, the PC speaker is barely audible, and I know from other videos of this computer on YouTube that it should be plenty loud. Finally, the power supply seems to be really weak. When the display backlight is at maximum brightness, you can hear the cooling fan slow down. When a floppy drive starts spinning, the fan slows down further, and when the heads on the floppy drive move, the display backlight significantly dims for an instant. I'm thinking maybe bad capacitors are causing both the speaker and power supply issues. Other than that, the computer works just fine. I can't wait to have some more free time and start playing with it.

But hey, the monitor came with that PC. How it connects then ?

The weak PSU needs new capacitors i think

The LCD performance - Could this be from age ? (something inside decomposing, ...)

The monitor is built-in and connects internally to the motherboard. The ability to connect to an external CGA monitor came in the form of an optional add-on card.

I suppose it could be from age, although I wouldn't think the chemistry of this display would be much different from other, simpler, perfectly readable LCD displays from the same era. If it was like this new, I would guess it is a limitation of having to address 150,000 pixels with the hardware of the time, so it was limited to the range of voltage it could apply to lit and unlit pixels.

I've recently noticed that the display looks much better when you look down at it from above, rather than facing it directly. Maybe that's the way it was always meant to be used?

Interestingly, in all other aspects the display is excellent. The refresh time is very quick (there is no discernible delay in switching pixels), and there is no ghosting artifacts on the display - almost as if it was active-matrix (maybe it is?). Apparently it's even dual-scan.

In these day, there may be a manual contrast/brightness adjustment for the LCD display

Yes, there is a contrast adjustment. But there's so little bias between unlit and lit pixels that it basically adjusts them in unison.

Aging capacitor on the vcc to the matrix controller ?

I have a Macintosh 512K

Don't think I added this yet.  But I got an HP Vita desktop added to my collection, along with a Gateway 2000 Cryistal Scan 1024N CRT monitor, Gateway 2000 5-Pin DIN keyboard (with 5-Pin DIN to PS/2 adaptor) and a mouse that I forget the brand of (I don't have it out).  I forget the specs of the machine but I can't check them too readily, but it works, it runs Windows 95 and the monitor works fine, though after you use it for a bit the monitor spazzes a little and then returns to normal, it acts like it wants to die.  The keyboard and mouse also work.  It was retired from weekly use about 3-5 years ago.

I had a couple CRT monitors do that and die somewhat later

In another case, i found out that there were ants coming into the monitor and getting thunderbolt attacked on the PCB, so each time the bunch of ants arced over the monitor flickered - Cleaning them out solved the problem