On 2020-01-08, Computer Nerd Kev  wrote:
> druck  wrote:
>> On 07/01/2020 21:34, Jim Jackson wrote:
>>>>> It seems to be this thing:
>>>>>
https://www.notebookcheck.net/Review-Iomega-eGO-Portable-500GB-USB-3-0.33106.0.
html
>>>>
>>>> It's spinning rust drive, that is going to be slower as main OS disc
>>>> than any sort of flash based medium. It would be OK for mass data storage.
>>>
>>> Go with the spinning rust - you might be surprised at the performance.
>>> Some people seem to think you always need the very fastest. It all depends
>>> on what you are planning to do.
>>
>> Performance for large sequential files is fine, but for use as a system
>> disc you need fast small random access performance, and for that
>> spinning rust has always been bad. Hence everyone moving to SSDs on
>> their PCs.
>
> If you want super performance matching the latest PCs you wouldn't
> start with a Pi in the first place. SD cards are hardly designed to
> compete with HDDs for speed anyway, and the OP's issue with them is
> long-term reliability not speed.

I suppose it's both important: long term reliability (you never want
it to ruin files in /home), and enough speed to run a desktop, doing
some gimping and blendering, Usenetting, video playback, etc. I also
have a 'netbook' (Acer Aspire One), but it can not do much, far slower
than the Pi.

If you type in a webbrowser on that netbook, you will sometimes have to
wait 15 seconds for the browser to catch up to where you are writing
(it was running Linux with a light desktop, or i3wm).  In terms of
formfactor however, the netbook is easier than a Pi with whatever else
you need with it (screen/keyboard, etc). Hence it would seem the Pi
has a nice niche use between a normal PC, and a 'netbook' type computer.

>>>>> I tried to plug it in just now, while the Pi 4B was running with power
>>>>> from the wall socket, and it crashed the operating system. The X-server
>>>>> crashed, it returned to the text console, and then seemed to lock up
>>>>> with some kind of file system errors being printed. It accepted no input
>>>>> from the keyboard anymore.
>>>>
>>>> It probably requires too much power, and caused a voltage dip. You'll
>>>> need to use a USB hub to provide the power most types of spinning rust
>>>> hard drive require.
>>>
>>> Quite a lot of modern spinners work perfectly well powered from Raspberry
>>> pi's. You do need an adequate power supply. And for the 4B that means one
>>> that supply 3 amps.
>>
>> But this one crashes the OP's Pi.

Right, though it is fine if you boot with all connected.

> When he plugs it in while the Pi is already booted. This will be due
> to the surge of current drawn by the HDD when it starts to spin up.
> When the Pi is running, the dip in voltage is enough to disrupt it.
> However when both Pi and HDD are powered on at the same time, the Pi
> is presumably in some sort of power-on reset state (a deliberate
> delay intended to avoid problems due to power-on voltage supply
> instability) so by the time it starts running the HDD has already
> got going and is no longer pulling too much current.

That is how it looks like. The failure is not consistent, because
sometimes I could still use the keyboard. This may be indicative of
something random like a power dip causing undefined behavior (I guess).

> So it may not be a problem so long as the HDD is never connected
> to a turned-on Pi. If the OP does want to do that, a higher-current
> power supply may or may not be the solution. If the problem is due
> to the resistance of the 5V lines on the Pi's circuit board causing
> a voltage drop, then the beefier power supply will make no
> difference. What you want is a direct wired connection from the power
> supply output to the USB socket that the HDD connects to. Or
> something clever using a capacitor and diodes could work too if done
> by someone with knowledge of electronics.

In my case I may eventually want to go for the fast and large 128 GB
thumb drive mentioned in this thread earlier, since it keeps things
small and fast, not to mention the large size. For now I simply use an
SSD card, which isn't a fast one (a rated '2' sandisk), with /var on
USB 2 stick). Everything works fine for now, fast enough.

Using a big external drive does hurt the form factor. Not a problem at
home, but cumbersome on the move. I had good experience taking the Pi 4B
on a trip, with a keyboard, drawing tablet and LCD screen (no external
drive). It does get to the point where you have a bunch of wires going
everywhere. Will have to get some kind of case to fit things in, so that
most can stay in it while you use it.

Also using the Pi as a normal home PC (using it right now), for when
I don't need to do something requiring more power (such as 3D world
rendering). It is nice how quiet it is, and that it is only using
little energy.

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