A couple of retros I'm working on.

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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-25 @ 19:33

So ..I guess I simply cannot use this SSD in the T4900
Made a new EZDRIVE floppy as I suspected the one I already made was damaged.
The new one booted and I followed the instructions.
It claimed it would make 4 partitions ..of around 2gb each ..
It did not..
It used the whole SSD and made one 7.XX gb FAT partition..
The T4900 still says no fixed disk.
FDISK still claims there are NO partitions..
So I'm having to assume this project is doomed.
..and most likely I'll have the same results with a CF .
I mounted the SSD in my main PC just to see what was there ..
A partition just under 8gb ...FAT ..and many files which make no sense to me..
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-25 @ 19:43

Perhaps you might take a look at what is claimed to be the latest bios update for the T4900CT Ian..
I'm attaching the link to this message ..
https://support.toshiba.com/support/mod ... 1073769832
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Re: A couple of retros I'm working on.

Postby IanB » 2018-2-25 @ 22:14

Vipersan wrote:FDISK still claims there are NO partitions..

Don't forget that after you have installed drive overlay software, you can't boot in the normal way from a floppy anymore.
You have to wait until the system boots from the hard drive and then there should be a prompt to press a key to boot from floppy (maybe CTRL)
This is because the drive overlay software has to load before any OS booted from floppy can see the full HD.

Vipersan wrote:Perhaps you might take a look at what is claimed to be the latest bios update for the T4900CT Ian..
I'm attaching the link to this message .

The readme says:

EIDE HARD DRIVE SUPPORT
-----------------------
The BIOS section for hard drive support has been upgraded to support
Enhanced IDE hard drive . This means that support for hard drives
larger than 528mb is now available. Check with your local Toshiba Sales
representative for a listing of compatible hard drives.

So upgrading to that BIOS should allow it to see the full 8GB which means no need for drive overlay software.
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-2-25 @ 22:37

Use this image and make a floppy out of it, then boot off it with a clean unformatted HDD drive ready.

The drive has to be totally clean (all zeroes) for this to work properly. Boot from the EZDrive disk and proceed with "Full Automatic Setup"

You need to have the bootdisk of the desired OS you want to install afterwards ready for it to be able to create partitions. For example Win95 bootdisk. When you insert one that is FAT 32 capable it will even ask you if you want that.

Proceed and ask if you have questions. I use this with ALL my laptops that have any form of SD or CF adapter or drive that is bigger than supported by BIOS. They all work flawlessly.
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-2-25 @ 22:40

PS: I f you get any error when doing Full Automatic Setup like "partition/sector error [...]" then just repeat the Full Automatic setup and you will be fine. This sometimes happen if there is something left in the HDDs boot sector.

ALSO: if EZDrive doesnt detect you SSD then it doesnt work with you T. Then you have to actually use a CF or SD adapter.
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-25 @ 22:50

I've downloaded the 909W version ..and will try it with a CF once a suitable adapter arrives..
In the meantime I'll keep trying with conventional mechanical drives.
The bios does show Enhanced mode already ..and it must already be working as the fitted drive is over 528mb ..
but still a now show for the SSD ..
which I can only assume is either not suitable or will need overlay.
cheers for the help guys.
800mb is simply not enough space ..even for win95
;)
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-2-26 @ 10:38

Overlay software might still be needed if the XT BIOS is unable to determine the C/H/S situation of the drive and everything except the initialization fails in order to translate for the BIOS.

I have one laptop that although it features an XT-BIOS still needs overlay software because although the drive is initialized, the BIOS cannot access it, regardless of C/H/S settings. In the end I gave up and just used overlay software.

Vipersan: Be sure that the drive/CF-card is completely empty. After attaching it and booting from the EZDisk, your drive should be detected and shown in the list at the bottom after EZDrive loaded. IF not, then your BIOS didnt even initialize the drive, which is possible if the drive is simply too new.
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-2-26 @ 11:19

jaZz_KCS wrote:Overlay software might still be needed if the XT BIOS is unable to determine the C/H/S situation of the drive and everything except the initialization fails in order to translate for the BIOS.

I have one laptop that although it features an XT-BIOS still needs overlay software because although the drive is initialized, the BIOS cannot access it, regardless of C/H/S settings. In the end I gave up and just used overlay software.

Vipersan: Be sure that the drive/CF-card is completely empty. After attaching it and booting from the EZDisk, your drive should be detected and shown in the list at the bottom after EZDrive loaded. IF not, then your BIOS didnt even initialize the drive, which is possible if the drive is simply too new.


Hi JZ ..when you say completely empty ..
Is it sufficient to just delete partition or data ..or is the an app to fill it with zeros ?

In other words ..how would you prepare say ..used CFs you bought off ebay..?
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-2-26 @ 13:22

I would completely wipe them (for example with dd on linux, effectively "zeroing" the drive), making sure that not only all data is deleted, but the boot sector also empty.

You don't HAVE to do that, but it's better to make sure there are no remnants of for example other older overlays present.

Regardless of the OS/Tool you're using, deleting all partitions, deleting the MBR with the tool of your choice would be sufficient.
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Re: A couple of retros I'm working on.

Postby IanB » 2018-2-26 @ 17:12

Vipersan wrote:is the an app to fill it with zeros ?

You can use HxD to do that, it's a freeware hex editor which can open raw disks as well as files.

https://mh-nexus.de/en/hxd/

You would have to do the following to blank a HD.
1. Run HxD as administrator
2. Select Extras then Open Disk
3. Select the Physical disk (not Logical) to be blanked from the list (bottom part of list)
4. Change the last two bytes of sector 0 from 55 AA to 00 00
5. Exit and save changes
Remove and reconnect the HD
This first change invalidates the partition table so when you reconnect, no partitions will be detected. If partitions are present you may get access denied if you try to blank the whole disk. You might not have to do the above if there are no partitions already defined.
Then do the following:
1. Run HxD as administrator
2. Select Extras then Open Disk
3. Select the Physical disk to be blanked from the list (bottom part of list)
4. Press CTRL-A to select all space on the HD
5. Select Edit then Fill selection with a 1 pass pattern of 00
6. Exit and save changes if prompted

The above might not work with large drives as it uses memory as an undo buffer but even just selecting the first few hundred sectors and blanking them will get rid of any remnants of drive overlay software.

Warning: Make sure you select the right drive! If you select the wrong one you might end up blanking your boot drive! After opening the drive you can check you have selected the right one by scrolling up and down which should make the drive access light flash (assuming you are using a USB adapter of some sort)
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-3-01 @ 10:30

I've successfully created a new win95 installation on one of my T4900CT toshiba laptops ...on an old 2gb ide 2.5 inch hard drive ..as I will be waiting a while yet for CF adapters.
This has all gone smoothly ...and when I checked for anything not installed during setup ..the only yellow question mark in the list says 'PCMCIA Card Services' ..
this is obviously pcmcia related ..but what exactly is missing ?
Should something be installed _ before_ I attempt to use pcmcia devices ?..if so what ?
Can anyone help me here ..
I guess I'm surprised win95 didn't pick this up during the installation.
rgds
VS
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-3-01 @ 15:08

I think my 486 chips have arrived ..
got a card this morning with another ransom demand ..
£16 to get them out of jail ..and yet they only cost £20 ..
I hate the way the UK customs exploit us Brits.
Too much snow and ice to go pay the bail money so it will just have to wait a day or so..
rgds
VS
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-3-01 @ 15:58

It's almost as bad here in Germany actually. Everything below EUR 20,45 (somewhere around 20 Euro) is free from outside the EU. Everything above this value: BAM! 19% Import Tax.
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-3-02 @ 13:38

Broke my 486 cpus out of jail
Keep in mind the original cost was around £20 ..plus postage
Here is the breakdown of the jailbreak charges..

Import duty = Zero
Excise duty = Zero
VAT = £7.45
Royal mail international Handling Fee = £8.00

Why ????
Surely this is close to pay up or we will send the boys round with baseball bats ...and take your kneecaps.

Criminal I calls it.
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Re: A couple of retros I'm working on.

Postby jaZz_KCS » 2018-3-02 @ 20:59

Kneel (and pay), peasant!

:P
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Re: A couple of retros I'm working on.

Postby Hamby » 2018-3-03 @ 16:22

Well, I got my other parts yesterday; the 4GB CF card, the IDE to CF adapter, the contact cleaner, the lithium grease, the thermal paste (for the 486 CPU I already got), the chip puller, the keycap puller.

Now I just need to arrange to get the bios chips from IanB (or buy a burner/eraser), and I can update my T5200.
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-3-03 @ 19:58

Not a lot done recently ..
I still have to do any mods to take full advantage ..whatever those might be.
..and of course ..I still have the simm mod to do when my ribbon cable finally gets here ..
Still ..with some gentle lifting with a flat blade butter knife ..I eventually got the 386 out and swapped in the 486.
A start I suppose..
Quite hot-ish to the touch ..so some sort of cooling needed I think..?
suggestions welcomed ..though it would have to be very low profile to clear the Keyboard.
rgds
VS
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Re: A couple of retros I'm working on.

Postby IanB » 2018-3-04 @ 01:29

Vipersan wrote:Quite hot-ish to the touch ..so some sort of cooling needed I think..?
suggestions welcomed ..though it would have to be very low profile to clear the Keyboard.

I looked at this recently. Technically it doesn't need a heatsink but it may depend on the ambient temperature.
The chip is designed to work up to 85 degrees Centigrade so I fitted one and ran it for several hours with the unit reassembled. The CPU got up to 70 degrees so still within the acceptable range but this was with an ambient temp of 22 degrees C so if ambient was higher, the CPU would get correspondingly higher. With a heatsink fitted the CPU got up to 60 - 65 degrees C which is better but not by a great deal because there isn't much airflow. I also tried a very low profile heatsink and fan which I think came off a very early video card and that kept it to 45 degrees C when run at low RPM to avoid adding extra fan noise. (Even then I had to file the front edge off the heatsink to get it to fit)

I haven't found a suitable heatsink/fan combination on Ebay but they do have 386 sized low profile heatsinks such as this:
https://www.ebay.co.uk/itm/Aluminium-He ... 3375161103
(select the 2pcs 37 * 37 * 6mm green northbridge heatsink)
There is also a 10mm high one of similar size but you would probably have to file or cut part of the front of it off to get it to fit under the sloping metal RF shield.

There is no mounting mechanism for this type of heatsink so you have to stick it on either with special heatsink adhesive or double sided tape such as this:
https://www.ebay.co.uk/itm/Thermal-Cond ... 3448884984
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-3-04 @ 12:07

Thanks Ian ..
Trying an idea myself today ..
No thermal paste involved as yet ..but a copper piece cut as in the photo ..which I'm hoping will transfer heat up to the steel drive frame..
no anchor point below the cpu so left a curled section which hopefully will act as a spring so that the keyboard itself provides some downward force when fitted ..
and there is room on top of the plate above the cpu...for aluminium fins (a proper low profile heatsink ) to be glued.
rgds
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Re: A couple of retros I'm working on.

Postby Vipersan » 2018-3-04 @ 12:46

The temperature of the HD/FDD cage is slowly rising ..so some heat transfer must be taking place..
A good sign..
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