Friday, 01-Mar-2024 13:59:15 GMT
|RAM or EPROM Packs?
How to decide what to get
The Z88 comes with
32K RAM 'built-in' memory. This is just enough to try out the
examples given in the manual before you run out.
If you want to use
your Z88, you need more RAM because it uses RAM as working memory
and for storing files.
RAM gets used for everything
You should use other
devices to back your files up, but the first need to be stored
in RAM otherwise you are unable to get them to the other devices.
RAM should be added (in slot 1 (or slot 2 if using OZ 4.x)) initially. This makes the Z88 an 'expanded' machine, the preferred configuration.
used by Z88
Cambridge Computer Memory
Card booklet (500K)
The Z88 uses some
of the extra RAM for itself internally for Applications and BBC
BASIC. You will quickly discover that you need more RAM than
The following example
assumes using a 20K document in Pipedream with a 128K RAM Pack.
used by Z88 (expanded machine)
amount used by Pipedream
required to store the file in :RAM.1
Remember If you have not got enough
space to save the file to RAM, you will not be able to save it
to the EPROM Pack or transfer the file to another computer.
Note If you put your RAM in slot
2 then the Z88 will not be an expanded machine.
Now that you have
enough RAM, all you need to decide is how big the EPROM should
be to save your life's work to before the Z88 loses it due to the battery going flat or the Z88 crashes. Unlike
the RAM where you can delete individual files to gain extra space,
all the files on the EPROM are deleted when the device is formatted.
So you need enough RAM to store these files whilst you do that.
What do I do?
I have used a 1M or 512K RAM
pack. I have never run out of RAM with the 1M!
Computer The Z88 Card Exchange System (864K)
EPROM are used for file
storage or as ROMs for applications and
are like disks on a PC or Mac..
Unlike RAM packs they retain the information when the batteries
Save your important
files on a Flash
EPROM or EPROM pack.
Once you have saved
a file onto the pack, it will remain there allowing the pack
to be removed without losing any data.
There were 3 sizes,
32K, 128K and 256K.
do not have any 32K EPROMS left and only have limited supplies of
the other sizes. They have been superseded due to the arrival of the
Cambridge Computer Memory
Card booklet (500K)
a disk and an EPROM pack.
Individual files can
not be physically deleted by overwriting them. Instead the 'old'
file is marked and the new file is saved at the beginning of
the cleared area. This means that if you saved a file that is
2K long three times, 6K will be used.
Underside of EPROM showing window to allow UV light to erase
Files are erased
- formatting the entire
EPROM either by using an EPROM eraser (for the EPROM)
- or by using the the
command (in the Flash EPROM).
By using two packs,
files that need to be kept can be copied to RAM and then onto
another EPROM pack before formatting the full EPROM. EPROMs and
Flash EPROMs can be reused again after formatting.
Flash cards are used for file storage or as ROMs for applications and are like disks on a PC or Mac.
were first used from 14th September 1997 until 27th December 2004 and
could only be written to when in slot 3. They have been replaced using
the AMD chip.
|There are issues using this card with OZ 4.x Please do not update this card with the OZ image until it is found.
Turbo/ RAM Card
From OZ4.6.2 in slot
1, this card allows running Applications in RAM by using a faster decode chip. This gives an expanded Z88 with
- 512K RAM,
- and a File Area.
This is a RAM
If removed, a HARD reset is required
The Z88 is only able to write
or read to or from an EPROM pack. When you save the same file
twice, the Z88 only marks the old file as being deleted, it does
not reclaim the space back. The EPROM Eraser allows you to clear
the EPROM, to remove all the files, so that it can be used again.
The EPROM pack has
a hole to expose the window on the EPROM device inside the pack
to allow the light from the eraser to erase the EPROM. The EPROM
pack is pushed right into the eraser to turn on the light and
erase the pack.
EPROM Erasers formats
EPROMs allowing them to be used again. Unlike disks, individual
files cannot be erased.
Mains operated (240v
AC) it has a 20 minute timer to erase the EPROM pack whatever
We have reduced the
price of this item due to the arrival of the Flash EPROM!
You can use this to
erase ordinary EPROMs provided you make a carrier 2" wide
to place the EPROM into the eraser instead of using an EPROM
bulbs for the old and new style EPROM Erasers are no longer available,
but then at these prices - who cares?
Computer EPROM Eraser Instructions (946K)
EPROMs 24-28 pin
x 50mm 2" x 2"
x 87w x 83d mm
v No mains plug fitted
replaceable - uses special UV QUARTZ bulb
|MC14060BCP 14-Bit Binary Counter and Oscillator
there any other way to erase an EPROM ?
The following suggestions
have been made.
- I usually leave mine
on the window sill for a while (to let the sun do its work).
This can take some time in the winter, but get a few high UV
days this time of year and you're laughing.
- What about a tanning
lamp, or one of those children's spy pens (writes invisibly until
you illuminate with a UV source in the end of the pen - can be
bought for £1!).
- I tried that once
and found that the lamp also melted the EPROM case. When I finally
got the EPROM out I discovered that the files had not been erased
- There is a particular
frequency in the UV spectrum that erases the EPROM. - Yep, you
need a high-
intensity UV source of wavelength 253.7nm. There's a DIY project I keep on meaning to try.
- It uses a germicidal
uv fluorescent tube, which (as you might have guessed) is not
something you want to expose yourself to!
- A lot of modern filters
in garden ponds use these tubes, so if you have a friend who
has fish try popping the EPROM inside the filter enclosure for
a bit :-)
- The tanning lamp
I used certainly wasn’t on the right frequency but it did
get me ‘browned off.’
- When the Z88 User
Club was running they offered a service to erase EPROM for £5
We can offer that service if you want but in the long run it
doesn’t help and here is the reason why.
- Umm – I’ve
got a lot of files on my Z88, I should really back them up onto
my EPROM just in case the Z88 looses them.
- I’ve got a 128K
EPROM pack; I could put them on there.
- I don’t really
want to fill it up because I haven’t got an EPROM eraser.
- Oh bother –
my Z88 has just crashed – I’ve lost all my files.
So the moral of the
If you want to use the EPROM packs please invest in the EPROM
eraser, otherwise you will not use the EPROM and the benefit
you would have will not be realised. The only exception to this
is if you are using the EPROM to store Applications, then having
an EPROM eraser is not so critical.
|Cable - Printer (Parallel)
|Cable - Printer
|Z88 Dummy EPROM Case
(Erase DIL EPROMS Using The Z88 ERASER)
|Flash EPROM (1M)
Flash EPROM (1M) LED Upgrade
Flash EPROM (512K) / 512K RAM
|Mains Adapter (220v)
|Modem 300/1200-software & cable
|Power Supply (90-264v)
pack (1M) (low power)
|RAM pack (1M) (CC)
|RAM pack (512K)
|RAM pack (128K)
|Topper - Heavy Duty Version
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