Hi,
Fragmentation will happen as long as new information is written in places that'll cause problems for fast reading later. Also, while something is running, the operating system will still need to access things on disk if asked by the program.
As for swapping configurations: in theory, yes as long as the versions are compatible enough to not cause visible side effects. For example, if one swaps configurations between stable and next branches, that could raise problems in that some things required by next snapshots might not be present.
As for the add-on being the culprit: could be. One thing to try though: what if Roger runs his portable copy with all add-ons disabled? If that improves performance, then it could be an add-on, if not, we should try something else.
Implicating file systems: Roger did say this is an internal drive, hence I put more weight on possible fragmentation and data movement issues.
Cheers,
Joseph

-----Original Message-----
From: nvda@nvda.groups.io [mailto:nvda@nvda.groups.io] On Behalf Of Didier Colle
Sent: Friday, January 19, 2018 3:40 PM
To: nvda@nvda.groups.io
Subject: Re: [nvda] Portable version degrading

Dear Joseph, roger, all,


@Joseph: not sure to understand what point you try to make. Is your suggestion there is indeed a filesystem problem as the root cause?


trying to recapitulate a few things:

* "it can make it appear that the add on is defective or has a bug while
it really doesn't."

@Roger: for any further meaningful diagnosis, I believe a more concrete
symptom description is needed? (how does such "would be" bug manifestate
itself? Is it always the same "would be" bug or do many "would be" bugs
appear randomly? when do such "would be" bugs appear (during loading,
during execution of the add-on)?)

* "there's no file system errors"

I guess that means there are no issues with the
physical/electronic/magnetic integrity of the storage medium itself (or
that the filesystem has set them aside such that they are not used
anymore). In case corrupted/broken blocks on the storage medium would be
the root cause, something should be found in the logs as loading the
relevant python modules should throw an exception (if these exceptions
are not logged, it should be possible to do so). Therefore, I dismiss
storage medium/filesystem corruption as root cause of the above
mentioned "would be" bugs (assuming bugs have to be interpreted as
broken functionality).


* "I also notice a few functions of nvda either don't work at all or
nvda gets very sluggish in responsiveness"
@Roger: again, for any meaningfull diagnosis, provide a more concrete
symptiom description. What functions are you exactly speaking about?
What does "not work at all" exactly mean: do you mean sluggishness with
extremely long / infinite response times? Or do you get errors? or ...
Is the sluggishness general or does it happen in those specific
functions? What do you mean by sluggishness: response in only a second?
A few seconds? A minute or more? When does sluggishness happen: at time
of loading add-on/modules or continuously or ...?
* "... nor any fragmenting.". Statement from Joseph: "In case of Roger's
issue: a possible contributing factor is constant add-on updates. He
uses an add-on that is updated on a regular basis, .. ..., potentially
fragmenting bits of files ..."
The two statements appear to me as contradictory. Fragmentation may be a
root cause of sluggishness, but only when access to storage medium is
needed and not during general execution which typically takes place from
RAM rather then from disc. Therefore, fragmentation issues appear very
unlikely to me.

* "while the installed version is always stable as a rock." and "I use
the portable copy to test a couple add ons"
@Roger: how much do you use one and the other? How much usage does it
take before the portable copy gets degraded?
The two statements suggest there is a problem with the portable copies.
However, there seems to be nobody else experiencing the same problem.
Thus, I would translate this into the following question that you would
need to test/investigage further: is there a conflict between the
portable copies and your specific system setup, or is the issue caused
by the add-ons under test?
To test the former possibility, why not using a fresh portable copy
replicating the setup of your installed version instead of that
installed version for a while?
To test the latter that would probably require moving the add-on testing
to the installed version: I guess you are using the portable version for
this purpose, exactly to avoid messing up the installed version. Would
you have the possibility to do the testing in for example a virtual
machine, such that you can test on an installed instead of a portable
copy version, while not messing up your main system with this testing?
Joseph, anyone else: is there a (possibly more cumbersome) way to
perform testing on an installed version while keeping at all times a
possibility to revert back to a stable/clean situation? (e.g., having a
.bat script that swaps configuration file and add-on directories between
stable and testing versions and that can easily be executed in between
exiting nvda and restarting it?)
In case none of the above options is tried, my suggestions would be then
to regularly take snapshot copies of your portable copy such that when
degradation takes place a diff between stable and degraded version can
be taken and investigated.

In summary, I believe:
1) a much more concrete/detailed/... symptom description is needed
before any meaningful statements regarding diagnosis is possible;
2) with the info I have, filesystem/storage medium problems/corruptions
are very unlikely.
3) further testing/investigation is needed in order to support/dismiss
certain hypotheses.

Kind regards,

Didier

On 19/01/2018 18:19, Joseph Lee wrote:

Hi,
It'll depend on what type of drive it is. If it's a traditional hard drive,
it'll degrade as data moves around, creating the need for defragmentation.
This is especially the case when data is repeatedly written and the file
system is asked to find new locations to hold the constantly changing data.
In case of solid-state drives, it'll degrade if the same region is written
repeatedly, as flash memory has limited endurance when it comes to data
reads and writes.
In case of Roger's issue: a possible contributing factor is constant add-on
updates. He uses an add-on that is updated on a regular basis, putting
strain on part of the drive where the add-on bits are stored. Thus, some
drive sectors are repeatedly bombarded with new information, and one way
operating systems will do in this case is move the new data somewhere else
on the drive, potentially fragmenting bits of files (I'll explain in a
moment). Thus one solution is to not test all add-on updates, but that's a
bit risky as Roger is one of the key testers for this add-on I'm talking
about.
Regarding fragmentation and what not: the following is a bit geeky but I
believe you should know about how some parts of a file system (an in
extension, operating systems) works, because I believe it'll help folks
better understand what might be going on:
Storage devices encountered in the wild are typically organized into many
parts, typically into blocks of fixed-length units called "sectors". A
sector is smallest unit of information that the storage device can present
to the outside world, as in how much data can be held on a storage device.
For example, when you store a small document on a hard disk drive (HDD) and
when you wish to open it in Notepad, Windows will ask a module that's in
charge of organizing and interpreting data on a drive (called a file system)
to locate the sector where the document (or magnets or flash cells that
constitute the document data) is stored and bring it out to you. To you, all
you see is the path to the document, but the file system will ask the drive
controller (a small computer inside hard disks and other storage devices) to
fetch data in a particular sector or region. Depending on what kind of
storage medium you're dealing with, reading from disks may involve waiting
for a platter with desired sector to come to the attention of a read/write
head (a thin magnetic sensor used to detect or make changes to magnetic
fields) or peering inside windows and extracting electrons trapped within.
This last sentence is a vivid description of how hard disks and solid-state
drives really work behind the scenes, respectively.
But storage devices are not just meant for reading things for your
enjoyment. Without means of storing new things, it becomes useless.
Depending on the medium you've got, when you save something to a storage
device, the file system in charge of the device will ask the drive
controller to either find a spot on a disk filled with magnets and change
some magnets, or apply heat pressure to dislodge all cells on a block, erase
the block, add new things, and fill the empty block with modified data
(including old bits). You can imagine how tedious this can get, but as far
as your work is concerned, it is safe and sound.
Now imagine you wish to read and write repeatedly on a storage device. The
file system will repeatedly ask the drive hardware to fetch data from
specific regions, and will look for new locations to store changes. On a
hard drive, because there are limited number of heads and it'll take a while
for desired magnetic region to come to attention of one, read speed is slow,
hence increased latency (latency refers to how long you have to wait for
something to happen). When it comes to saving things to HDD's, all the drive
needs to do is tell the read/write head to change some magnets wherever it
wishes, hence data overriding is possible and easy. But operating systems
(rather, file systems) are smarter than that, as we'll see below.
In case of solid-state drives, reading data is simple as looking up the
address (or sector) where the electrons comprising the data you want is
saved (akin to walking down a street grid), so no need to wait for a sensor
to wait for something to happen. This is the reason why solid-state drives
appear to respond fast when reading something. On the other hand, writing or
injecting electrons is very slow because the drive needs to erase the entire
block before writing new data. In other words, just changing a letter in a
document and saving it to an SSD involves a lot of work, hence SSD's are
slower when it comes to writing new things, but because of the underlying
technology in use, it is way faster than hard disks.
As hinted above, file systems are smarter than drive controllers to some
extent. If data is written to a drive, the drive controller will process
whatever it comes along its path. But file systems won't let drive
controllers get away with that: file systems such as NTFS (New Technology
File System) will schedule data writes so it'll have minimal impact on the
lifespan of a storage device. For hard disks, it'll try its best to tell the
drive to store file data in consecutive locations in one big batch, but that
doesn't always work. For SSD's, the file system will ask the drive to
storage new information in different cells so all regions can be used
equally (at least for storing new information; this is called ware
leveling). One way to speed things up is asking the drive to reorganize data
so file fragments can be found in consecutive sectors or trim deleted
regions so fresh information can be written to more blocks (for HDD's and
SSD's, respectively), and this operation itself is tedious and produce bad
results if not done correctly and carefully.

I do understand the above explanation is a bit geeky, but I believe you need
to know some things about how things work. It is also a personal exercise to
refresh my memory on certain computer science topics (I majored in it not
long ago, and my interests were mostly hardware and operating systems, hence
I was sort of naturally drawn to screen reader internals and how it
interacts with system software).
Cheers,
Joseph

-----Original Message-----
From: nvda@nvda.groups.io [mailto:nvda@nvda.groups.io] On Behalf Of Roger
Stewart
Sent: Friday, January 19, 2018 7:58 AM
To: nvda@nvda.groups.io
Subject: Re: [nvda] Portable version degrading

The problem with this discussion is my portable version is on an internal
hard drive. So why is this degrading?

Nothing else on this drive has any trouble and I've checked, and there's no
file system errors nor any fragmenting.


Roger












On 1/19/2018 8:28 AM, Antony Stone wrote:

USB drives do need to be unmounted before removing them, otherwise there

is

the risk of file system corruption. Precisely the same is true for

external

hard drives, floppy disks, or any other writeable medium you can

temporarily

attach to a computer.

I've never seen a USB thumb drive fall apart, and I think they're

considerably

more robust than floppy disks, which is basically what they replaced. You

can

also drop them on the floor with a good deal more confidence of them

working

afterwards than if you drop an external hard disk.

Yes, they're vulnerable to static electricity; that's why most of them

have

plastic caps to put over the contacts or a slider to retract the contacts

into

the body.

My experience is that if they're treated reasonably they work very well.

If

they're mistreated they'll give as many problems as any other mistreated
storage medium.


Antony.

On Friday 19 January 2018 at 15:17:36, tonea.ctr.morrow@... wrote:

A few years back, I had a job for three years where people brought me

their

files on USB thumb drives. These things are horrible in terms of
long-life. The really do have to be unmounted prior to removing from the
computer or they get corrupted. They physically fall apart easily. And,
the hardware inside seems to be more vulnerable to static electricity

data

loss than other portable drives, certainly more vulnerable than most
computers.



I would think that would be the problem.



Tonea



-----Original Message-----

I've noticed over the past couple years that my portable install of nvda
will sometimes degrade or get a bit corrupted over time all by itself
while the installed version is always stable as a rock. Does anyone know
why this is and is there any way to prevent this from happening? I use
the portable copy to test a couple add ons and if the portable version
corrupts, it can make it appear that the add on is defective or has a bug
while it really doesn't. Deleting the portable copy and making a new one
will clear it up. I also notice a few functions of nvda either don't

work

at all or nvda gets very sluggish in responsiveness and this all gets

back

to normal after a complete flush and remake of the portable version. As

I

say, this never has happened at all with my installed copy on the same
computer.





Roger

Hi,

My husband and I are both totally blind and just had a nightmare of
installing a fresh copy of Windows 10 so that we could get the latest
build. Before this we were happily using Real Speak Tom with the
latest build of NVDA as this is the best voice for me, with a slight
hearing impairment. We can't seem to get this voice installed where it
needs to go so that it can be used. I'd heard there were some voices
that could not be used anymore with the latest Windows build. Please
tell me this is not one of them and if it can still be used, please,
would someone help me in doing this? Please? Thanks. We're currently
using Microsoft Mark as it's better for me than David, but I still
have some trouble with it and would appreciate any help from anyone
that could.


On 1/19/2018 7:21 PM, Joseph Lee wrote:

Hi,
Fragmentation will happen as long as new information is written in
places that'll cause problems for fast reading later. Also, while
something is running, the operating system will still need to access
things on disk if asked by the program.
As for swapping configurations: in theory, yes as long as the
versions are compatible enough to not cause visible side effects. For
example, if one swaps configurations between stable and next
branches, that could raise problems in that some things required by
next snapshots might not be present.
As for the add-on being the culprit: could be. One thing to try
though: what if Roger runs his portable copy with all add-ons
disabled? If that improves performance, then it could be an add-on,
if not, we should try something else.
Implicating file systems: Roger did say this is an internal drive,
hence I put more weight on possible fragmentation and data movement
issues.
Cheers,
Joseph

-----Original Message-----
From: nvda@nvda.groups.io [mailto:nvda@nvda.groups.io] On Behalf Of
Didier Colle
Sent: Friday, January 19, 2018 3:40 PM
To: nvda@nvda.groups.io
Subject: Re: [nvda] Portable version degrading

Dear Joseph, roger, all,


@Joseph: not sure to understand what point you try to make. Is your
suggestion there is indeed a filesystem problem as the root cause?


trying to recapitulate a few things:

* "it can make it appear that the add on is defective or has a bug while
it really doesn't."

@Roger: for any further meaningful diagnosis, I believe a more concrete
symptom description is needed? (how does such "would be" bug manifestate
itself? Is it always the same "would be" bug or do many "would be" bugs
appear randomly? when do such "would be" bugs appear (during loading,
during execution of the add-on)?)

* "there's no file system errors"

I guess that means there are no issues with the
physical/electronic/magnetic integrity of the storage medium itself (or
that the filesystem has set them aside such that they are not used
anymore). In case corrupted/broken blocks on the storage medium would be
the root cause, something should be found in the logs as loading the
relevant python modules should throw an exception (if these exceptions
are not logged, it should be possible to do so). Therefore, I dismiss
storage medium/filesystem corruption as root cause of the above
mentioned "would be" bugs (assuming bugs have to be interpreted as
broken functionality).


* "I also notice a few functions of nvda either don't work at all or
nvda gets very sluggish in responsiveness"
@Roger: again, for any meaningfull diagnosis, provide a more concrete
symptiom description. What functions are you exactly speaking about?
What does "not work at all" exactly mean: do you mean sluggishness with
extremely long / infinite response times? Or do you get errors? or ...
Is the sluggishness general or does it happen in those specific
functions? What do you mean by sluggishness: response in only a second?
A few seconds? A minute or more? When does sluggishness happen: at time
of loading add-on/modules or continuously or ...?
* "... nor any fragmenting.". Statement from Joseph: "In case of Roger's
issue: a possible contributing factor is constant add-on updates. He
uses an add-on that is updated on a regular basis, .. ..., potentially
fragmenting bits of files ..."
The two statements appear to me as contradictory. Fragmentation may be a
root cause of sluggishness, but only when access to storage medium is
needed and not during general execution which typically takes place from
RAM rather then from disc. Therefore, fragmentation issues appear very
unlikely to me.

* "while the installed version is always stable as a rock." and "I use
the portable copy to test a couple add ons"
@Roger: how much do you use one and the other? How much usage does it
take before the portable copy gets degraded?
The two statements suggest there is a problem with the portable copies.
However, there seems to be nobody else experiencing the same problem.
Thus, I would translate this into the following question that you would
need to test/investigage further: is there a conflict between the
portable copies and your specific system setup, or is the issue caused
by the add-ons under test?
To test the former possibility, why not using a fresh portable copy
replicating the setup of your installed version instead of that
installed version for a while?
To test the latter that would probably require moving the add-on testing
to the installed version: I guess you are using the portable version for
this purpose, exactly to avoid messing up the installed version. Would
you have the possibility to do the testing in for example a virtual
machine, such that you can test on an installed instead of a portable
copy version, while not messing up your main system with this testing?
Joseph, anyone else: is there a (possibly more cumbersome) way to
perform testing on an installed version while keeping at all times a
possibility to revert back to a stable/clean situation? (e.g., having a
.bat script that swaps configuration file and add-on directories between
stable and testing versions and that can easily be executed in between
exiting nvda and restarting it?)
In case none of the above options is tried, my suggestions would be then
to regularly take snapshot copies of your portable copy such that when
degradation takes place a diff between stable and degraded version can
be taken and investigated.

In summary, I believe:
1) a much more concrete/detailed/... symptom description is needed
before any meaningful statements regarding diagnosis is possible;
2) with the info I have, filesystem/storage medium problems/corruptions
are very unlikely.
3) further testing/investigation is needed in order to support/dismiss
certain hypotheses.

Kind regards,

Didier

On 19/01/2018 18:19, Joseph Lee wrote:

Hi,
It'll depend on what type of drive it is. If it's a traditional hard
drive,
it'll degrade as data moves around, creating the need for
defragmentation.
This is especially the case when data is repeatedly written and the
file
system is asked to find new locations to hold the constantly
changing data.
In case of solid-state drives, it'll degrade if the same region is
written
repeatedly, as flash memory has limited endurance when it comes to data
reads and writes.
In case of Roger's issue: a possible contributing factor is constant
add-on
updates. He uses an add-on that is updated on a regular basis, putting
strain on part of the drive where the add-on bits are stored. Thus,
some
drive sectors are repeatedly bombarded with new information, and one
way
operating systems will do in this case is move the new data
somewhere else
on the drive, potentially fragmenting bits of files (I'll explain in a
moment). Thus one solution is to not test all add-on updates, but
that's a
bit risky as Roger is one of the key testers for this add-on I'm
talking
about.
Regarding fragmentation and what not: the following is a bit geeky
but I
believe you should know about how some parts of a file system (an in
extension, operating systems) works, because I believe it'll help folks
better understand what might be going on:
Storage devices encountered in the wild are typically organized into
many
parts, typically into blocks of fixed-length units called "sectors". A
sector is smallest unit of information that the storage device can
present
to the outside world, as in how much data can be held on a storage
device.
For example, when you store a small document on a hard disk drive
(HDD) and
when you wish to open it in Notepad, Windows will ask a module
that's in
charge of organizing and interpreting data on a drive (called a file
system)
to locate the sector where the document (or magnets or flash cells that
constitute the document data) is stored and bring it out to you. To
you, all
you see is the path to the document, but the file system will ask
the drive
controller (a small computer inside hard disks and other storage
devices) to
fetch data in a particular sector or region. Depending on what kind of
storage medium you're dealing with, reading from disks may involve
waiting
for a platter with desired sector to come to the attention of a
read/write
head (a thin magnetic sensor used to detect or make changes to magnetic
fields) or peering inside windows and extracting electrons trapped
within.
This last sentence is a vivid description of how hard disks and
solid-state
drives really work behind the scenes, respectively.
But storage devices are not just meant for reading things for your
enjoyment. Without means of storing new things, it becomes useless.
Depending on the medium you've got, when you save something to a
storage
device, the file system in charge of the device will ask the drive
controller to either find a spot on a disk filled with magnets and
change
some magnets, or apply heat pressure to dislodge all cells on a
block, erase
the block, add new things, and fill the empty block with modified data
(including old bits). You can imagine how tedious this can get, but
as far
as your work is concerned, it is safe and sound.
Now imagine you wish to read and write repeatedly on a storage
device. The
file system will repeatedly ask the drive hardware to fetch data from
specific regions, and will look for new locations to store changes.
On a
hard drive, because there are limited number of heads and it'll take
a while
for desired magnetic region to come to attention of one, read speed
is slow,
hence increased latency (latency refers to how long you have to wait
for
something to happen). When it comes to saving things to HDD's, all
the drive
needs to do is tell the read/write head to change some magnets
wherever it
wishes, hence data overriding is possible and easy. But operating
systems
(rather, file systems) are smarter than that, as we'll see below.
In case of solid-state drives, reading data is simple as looking up the
address (or sector) where the electrons comprising the data you want is
saved (akin to walking down a street grid), so no need to wait for a
sensor
to wait for something to happen. This is the reason why solid-state
drives
appear to respond fast when reading something. On the other hand,
writing or
injecting electrons is very slow because the drive needs to erase
the entire
block before writing new data. In other words, just changing a
letter in a
document and saving it to an SSD involves a lot of work, hence SSD's
are
slower when it comes to writing new things, but because of the
underlying
technology in use, it is way faster than hard disks.
As hinted above, file systems are smarter than drive controllers to
some
extent. If data is written to a drive, the drive controller will
process
whatever it comes along its path. But file systems won't let drive
controllers get away with that: file systems such as NTFS (New
Technology
File System) will schedule data writes so it'll have minimal impact
on the
lifespan of a storage device. For hard disks, it'll try its best to
tell the
drive to store file data in consecutive locations in one big batch,
but that
doesn't always work. For SSD's, the file system will ask the drive to
storage new information in different cells so all regions can be used
equally (at least for storing new information; this is called ware
leveling). One way to speed things up is asking the drive to
reorganize data
so file fragments can be found in consecutive sectors or trim deleted
regions so fresh information can be written to more blocks (for
HDD's and
SSD's, respectively), and this operation itself is tedious and
produce bad
results if not done correctly and carefully.

I do understand the above explanation is a bit geeky, but I believe
you need
to know some things about how things work. It is also a personal
exercise to
refresh my memory on certain computer science topics (I majored in
it not
long ago, and my interests were mostly hardware and operating
systems, hence
I was sort of naturally drawn to screen reader internals and how it
interacts with system software).
Cheers,
Joseph

-----Original Message-----
From: nvda@nvda.groups.io [mailto:nvda@nvda.groups.io] On Behalf Of
Roger
Stewart
Sent: Friday, January 19, 2018 7:58 AM
To: nvda@nvda.groups.io
Subject: Re: [nvda] Portable version degrading

The problem with this discussion is my portable version is on an
internal
hard drive.  So why is this degrading?

Nothing else on this drive has any trouble and I've checked, and
there's no
file system errors nor any fragmenting.


Roger












On 1/19/2018 8:28 AM, Antony Stone wrote:

USB drives do need to be unmounted before removing them, otherwise
there

is

the risk of file system corruption. Precisely the same is true for

external

hard drives, floppy disks, or any other writeable medium you can

temporarily

attach to a computer.

I've never seen a USB thumb drive fall apart, and I think they're

considerably

more robust than floppy disks, which is basically what they
replaced.  You

can

also drop them on the floor with a good deal more confidence of them

working

afterwards than if you drop an external hard disk.

Yes, they're vulnerable to static electricity; that's why most of them

have

plastic caps to put over the contacts or a slider to retract the
contacts

into

the body.

My experience is that if they're treated reasonably they work very
well.

If

they're mistreated they'll give as many problems as any other
mistreated
storage medium.


Antony.

On Friday 19 January 2018 at 15:17:36, tonea.ctr.morrow@... wrote:

A few years back, I had a job for three years where people brought me

their

files on USB thumb drives. These things are horrible in terms of
long-life. The really do have to be unmounted prior to removing
from the
computer or they get corrupted. They physically fall apart easily.
And,
the hardware inside seems to be more vulnerable to static electricity

data

loss than other portable drives, certainly more vulnerable than most
computers.



I would think that would be the problem.



Tonea



-----Original Message-----

I've noticed over the past couple years that my portable install
of nvda
will sometimes degrade or get a bit corrupted over time all by itself
while the installed version is always stable as a rock. Does
anyone know
why this is and is there any way to prevent this from happening? 
I use
the portable copy to test a couple add ons and if the portable
version
corrupts, it can make it appear that the add on is defective or
has a bug
while it really doesn't.  Deleting the portable copy and making a
new one
will clear it up.  I also notice a few functions of nvda either don't

work

at all or nvda gets very sluggish in responsiveness and this all gets

back

to normal after a complete flush and remake of the portable
version.  As

I

say, this never has happened at all with my installed copy on the
same
computer.





Roger

Hi,

My husband and I are both totally blind and just had a nightmare of
installing a fresh copy of Windows 10 so that we could get the latest
build. Before this we were happily using Real Speak Tom with the
latest build of NVDA as this is the best voice for me, with a slight
hearing impairment. We can't seem to get this voice installed where it
needs to go so that it can be used. I'd heard there were some voices
that could not be used anymore with the latest Windows build. Please
tell me this is not one of them and if it can still be used, please,
would someone help me in doing this? Please? Thanks. We're currently
using Microsoft Mark as it's better for me than David, but I still
have some trouble with it and would appreciate any help from anyone
that could.


On 1/19/2018 7:21 PM, Joseph Lee wrote:

Hi,
Fragmentation will happen as long as new information is written in
places that'll cause problems for fast reading later. Also, while
something is running, the operating system will still need to access
things on disk if asked by the program.
As for swapping configurations: in theory, yes as long as the
versions are compatible enough to not cause visible side effects. For
example, if one swaps configurations between stable and next
branches, that could raise problems in that some things required by
next snapshots might not be present.
As for the add-on being the culprit: could be. One thing to try
though: what if Roger runs his portable copy with all add-ons
disabled? If that improves performance, then it could be an add-on,
if not, we should try something else.
Implicating file systems: Roger did say this is an internal drive,
hence I put more weight on possible fragmentation and data movement
issues.
Cheers,
Joseph

-----Original Message-----
From: nvda@nvda.groups.io [mailto:nvda@nvda.groups.io] On Behalf Of
Didier Colle
Sent: Friday, January 19, 2018 3:40 PM
To: nvda@nvda.groups.io
Subject: Re: [nvda] Portable version degrading

Dear Joseph, roger, all,


@Joseph: not sure to understand what point you try to make. Is your
suggestion there is indeed a filesystem problem as the root cause?


trying to recapitulate a few things:

* "it can make it appear that the add on is defective or has a bug
while it really doesn't."

@Roger: for any further meaningful diagnosis, I believe a more
concrete symptom description is needed? (how does such "would be" bug
manifestate itself? Is it always the same "would be" bug or do many
"would be" bugs appear randomly? when do such "would be" bugs appear
(during loading, during execution of the add-on)?)

* "there's no file system errors"

I guess that means there are no issues with the
physical/electronic/magnetic integrity of the storage medium itself
(or that the filesystem has set them aside such that they are not
used anymore). In case corrupted/broken blocks on the storage medium
would be the root cause, something should be found in the logs as
loading the relevant python modules should throw an exception (if
these exceptions are not logged, it should be possible to do so).
Therefore, I dismiss storage medium/filesystem corruption as root
cause of the above mentioned "would be" bugs (assuming bugs have to
be interpreted as broken functionality).


* "I also notice a few functions of nvda either don't work at all or
nvda gets very sluggish in responsiveness"
@Roger: again, for any meaningfull diagnosis, provide a more concrete
symptiom description. What functions are you exactly speaking about?
What does "not work at all" exactly mean: do you mean sluggishness
with extremely long / infinite response times? Or do you get errors? or ...
Is the sluggishness general or does it happen in those specific
functions? What do you mean by sluggishness: response in only a second?
A few seconds? A minute or more? When does sluggishness happen: at
time of loading add-on/modules or continuously or ...?
* "... nor any fragmenting.". Statement from Joseph: "In case of
Roger's
issue: a possible contributing factor is constant add-on updates. He
uses an add-on that is updated on a regular basis, .. ...,
potentially fragmenting bits of files ..."
The two statements appear to me as contradictory. Fragmentation may
be a root cause of sluggishness, but only when access to storage
medium is needed and not during general execution which typically
takes place from RAM rather then from disc. Therefore, fragmentation
issues appear very unlikely to me.

* "while the installed version is always stable as a rock." and "I
use the portable copy to test a couple add ons"
@Roger: how much do you use one and the other? How much usage does it
take before the portable copy gets degraded?
The two statements suggest there is a problem with the portable copies.
However, there seems to be nobody else experiencing the same problem.
Thus, I would translate this into the following question that you
would need to test/investigage further: is there a conflict between
the portable copies and your specific system setup, or is the issue
caused by the add-ons under test?
To test the former possibility, why not using a fresh portable copy
replicating the setup of your installed version instead of that
installed version for a while?
To test the latter that would probably require moving the add-on
testing to the installed version: I guess you are using the portable
version for this purpose, exactly to avoid messing up the installed
version. Would you have the possibility to do the testing in for
example a virtual machine, such that you can test on an installed
instead of a portable copy version, while not messing up your main system with this testing?
Joseph, anyone else: is there a (possibly more cumbersome) way to
perform testing on an installed version while keeping at all times a
possibility to revert back to a stable/clean situation? (e.g., having
a .bat script that swaps configuration file and add-on directories
between stable and testing versions and that can easily be executed
in between exiting nvda and restarting it?) In case none of the above
options is tried, my suggestions would be then to regularly take
snapshot copies of your portable copy such that when degradation
takes place a diff between stable and degraded version can be taken
and investigated.

In summary, I believe:
1) a much more concrete/detailed/... symptom description is needed
before any meaningful statements regarding diagnosis is possible;
2) with the info I have, filesystem/storage medium
problems/corruptions are very unlikely.
3) further testing/investigation is needed in order to
support/dismiss certain hypotheses.

Kind regards,

Didier

On 19/01/2018 18:19, Joseph Lee wrote:

Hi,
It'll depend on what type of drive it is. If it's a traditional hard
drive, it'll degrade as data moves around, creating the need for
defragmentation.
This is especially the case when data is repeatedly written and the
file system is asked to find new locations to hold the constantly
changing data.
In case of solid-state drives, it'll degrade if the same region is
written repeatedly, as flash memory has limited endurance when it
comes to data reads and writes.
In case of Roger's issue: a possible contributing factor is constant
add-on updates. He uses an add-on that is updated on a regular
basis, putting strain on part of the drive where the add-on bits are
stored. Thus, some drive sectors are repeatedly bombarded with new
information, and one way operating systems will do in this case is
move the new data somewhere else on the drive, potentially
fragmenting bits of files (I'll explain in a moment). Thus one
solution is to not test all add-on updates, but that's a bit risky
as Roger is one of the key testers for this add-on I'm talking
about.
Regarding fragmentation and what not: the following is a bit geeky
but I believe you should know about how some parts of a file system
(an in extension, operating systems) works, because I believe it'll
help folks better understand what might be going on:
Storage devices encountered in the wild are typically organized into
many parts, typically into blocks of fixed-length units called
"sectors". A sector is smallest unit of information that the storage
device can present to the outside world, as in how much data can be
held on a storage device.
For example, when you store a small document on a hard disk drive
(HDD) and
when you wish to open it in Notepad, Windows will ask a module
that's in charge of organizing and interpreting data on a drive
(called a file
system)
to locate the sector where the document (or magnets or flash cells
that constitute the document data) is stored and bring it out to
you. To you, all you see is the path to the document, but the file
system will ask the drive controller (a small computer inside hard
disks and other storage
devices) to
fetch data in a particular sector or region. Depending on what kind
of storage medium you're dealing with, reading from disks may
involve waiting for a platter with desired sector to come to the
attention of a read/write head (a thin magnetic sensor used to
detect or make changes to magnetic
fields) or peering inside windows and extracting electrons trapped
within.
This last sentence is a vivid description of how hard disks and
solid-state drives really work behind the scenes, respectively.
But storage devices are not just meant for reading things for your
enjoyment. Without means of storing new things, it becomes useless.
Depending on the medium you've got, when you save something to a
storage device, the file system in charge of the device will ask the
drive controller to either find a spot on a disk filled with magnets
and change some magnets, or apply heat pressure to dislodge all
cells on a block, erase the block, add new things, and fill the
empty block with modified data (including old bits). You can imagine
how tedious this can get, but as far as your work is concerned, it
is safe and sound.
Now imagine you wish to read and write repeatedly on a storage
device. The file system will repeatedly ask the drive hardware to
fetch data from specific regions, and will look for new locations to
store changes.
On a
hard drive, because there are limited number of heads and it'll take
a while for desired magnetic region to come to attention of one,
read speed is slow, hence increased latency (latency refers to how
long you have to wait for something to happen). When it comes to
saving things to HDD's, all the drive needs to do is tell the
read/write head to change some magnets wherever it wishes, hence
data overriding is possible and easy. But operating systems (rather,
file systems) are smarter than that, as we'll see below.
In case of solid-state drives, reading data is simple as looking up
the address (or sector) where the electrons comprising the data you
want is saved (akin to walking down a street grid), so no need to
wait for a sensor to wait for something to happen. This is the
reason why solid-state drives appear to respond fast when reading
something. On the other hand, writing or injecting electrons is very
slow because the drive needs to erase the entire block before
writing new data. In other words, just changing a letter in a
document and saving it to an SSD involves a lot of work, hence SSD's
are slower when it comes to writing new things, but because of the
underlying technology in use, it is way faster than hard disks.
As hinted above, file systems are smarter than drive controllers to
some extent. If data is written to a drive, the drive controller
will process whatever it comes along its path. But file systems
won't let drive controllers get away with that: file systems such as
NTFS (New Technology File System) will schedule data writes so it'll
have minimal impact on the lifespan of a storage device. For hard
disks, it'll try its best to tell the drive to store file data in
consecutive locations in one big batch, but that doesn't always
work. For SSD's, the file system will ask the drive to storage new
information in different cells so all regions can be used equally
(at least for storing new information; this is called ware
leveling). One way to speed things up is asking the drive to
reorganize data so file fragments can be found in consecutive
sectors or trim deleted regions so fresh information can be written
to more blocks (for HDD's and SSD's, respectively), and this
operation itself is tedious and produce bad results if not done
correctly and carefully.

I do understand the above explanation is a bit geeky, but I believe
you need to know some things about how things work. It is also a
personal exercise to refresh my memory on certain computer science
topics (I majored in it not long ago, and my interests were mostly
hardware and operating systems, hence I was sort of naturally drawn
to screen reader internals and how it interacts with system
software).
Cheers,
Joseph

-----Original Message-----
From: nvda@nvda.groups.io [mailto:nvda@nvda.groups.io] On Behalf Of
Roger Stewart
Sent: Friday, January 19, 2018 7:58 AM
To: nvda@nvda.groups.io
Subject: Re: [nvda] Portable version degrading

The problem with this discussion is my portable version is on an
internal hard drive. So why is this degrading?

Nothing else on this drive has any trouble and I've checked, and
there's no file system errors nor any fragmenting.


Roger












On 1/19/2018 8:28 AM, Antony Stone wrote:

USB drives do need to be unmounted before removing them, otherwise
there

is

the risk of file system corruption. Precisely the same is true for

external

hard drives, floppy disks, or any other writeable medium you can

temporarily

attach to a computer.

I've never seen a USB thumb drive fall apart, and I think they're

considerably

more robust than floppy disks, which is basically what they
replaced. You

can

also drop them on the floor with a good deal more confidence of
them

working

afterwards than if you drop an external hard disk.

Yes, they're vulnerable to static electricity; that's why most of
them

have

plastic caps to put over the contacts or a slider to retract the
contacts

into

the body.

My experience is that if they're treated reasonably they work very
well.

If

they're mistreated they'll give as many problems as any other
mistreated storage medium.


Antony.

On Friday 19 January 2018 at 15:17:36, tonea.ctr.morrow@... wrote:

A few years back, I had a job for three years where people brought
me

their

files on USB thumb drives. These things are horrible in terms of
long-life. The really do have to be unmounted prior to removing
from the computer or they get corrupted. They physically fall
apart easily.
And,
the hardware inside seems to be more vulnerable to static
electricity

data

loss than other portable drives, certainly more vulnerable than
most computers.



I would think that would be the problem.



Tonea



-----Original Message-----

I've noticed over the past couple years that my portable install
of nvda will sometimes degrade or get a bit corrupted over time
all by itself while the installed version is always stable as a
rock. Does anyone know why this is and is there any way to prevent
this from happening?
I use
the portable copy to test a couple add ons and if the portable
version corrupts, it can make it appear that the add on is
defective or has a bug while it really doesn't. Deleting the
portable copy and making a new one will clear it up. I also
notice a few functions of nvda either don't

work

at all or nvda gets very sluggish in responsiveness and this all
gets

back

to normal after a complete flush and remake of the portable
version. As

I

say, this never has happened at all with my installed copy on the
same computer.





Roger