How full to run Internal Flash Memory?

[frankxs]

With standard spinning disks, they are generally significantly slower when full or almost full. I think this is primarily due to the mechanical nature of the spinning disk and the time for the "arm" to move around to access the data. I suspect this is not true of "flash drives" like the 720's Internal Memory drive. Right?

Does anyone have any recommendations on how full is too full? Does it need "working space?" If you had, say, 30MB free, is that enough?

-Frank

 

[Z28]

frankxs
Based upon my being a high tech computer software developer, your initial statement about
spinning disks being slower when full is not correct. The programming logic used to
populate the disk and then to access the data determines access times. In the Windows
world what you said tends to be correct due to disk defragmentation. Periodic use of the
defrag functions should speed up that access.
Flash drives are also affected by programming logic used to populate and then retrieve the
data. Free space should not affect performance in either of the two types. Hope this helps
and has not been overly technical.

 

[frankxs]

frankxs
Based upon my being a high tech computer software developer, your initial statement about
spinning disks being slower when full is not correct. The programming logic used to
populate the disk and then to access the data determines access times. In the Windows
world what you said tends to be correct due to disk defragmentation. Periodic use of the
defrag functions should speed up that access.
Flash drives are also affected by programming logic used to populate and then retrieve the
data. Free space should not affect performance in either of the two types. Hope this helps
and has not been overly technical.

Hehe... based upon my being a computer systems engineer, as you said, I realize that fragmentation is one primary reason that spinning disk drives tend to get slower when capacity is reached. Coupled with this is the mechanical movement of the head/arm assembly frantically moving back and forth to locate all the fragments to load data. Fragmented data is "by design" in all the computer systems I've worked with (i.e. Unix derivatives/Windows/DOS). This is more efficient overall. Granted, some operating systems are better at managing it than others. Also, most (all?) 32bit+ OSes use virtual memory on the disk. This also creates a risk of running too low on disk space.

Anyway, what I am thinking: The 720 probably doesn't use "virtual memory" (or swap file if you prefer), but I don't know. The 720 has no mechanical head/arm to move around. Even considering fragmentation, which will exist to some extent, it should be somewhat minimum as compared to a computer with so many more write operations. After all, the 720 is primarily a read-only device with only an occasional write here and there for user preferences, I think. And even fragmented data should be accessed much faster than a computer due to not needing to move a mechanical head/arm to the location of the next fragment.

So... in the end, it seems like you could run the 720's Internal drive right down to the bare minimum without consequence. Hence, my question.

-Frank

 

[canderson]

Does anyone have any recommendations on how full is too full? Does it need "working space?" If you had, say, 30MB free, is that enough?

-Frank

As long as there's still memory left when a write occurs, you've got enough. And believe me, there's nothing you're going to do from the keypad that will come close to adding a 30MB load to the unit. I have a list of about 1200 geocaching waypoints with descriptive info for each that takes up only 90KB.

Writes don't occur immediately for every task, either. Many are held in DRAM and deferred until the unit is "shut down". For example, if the unit crashes/reboots while you're navigating to a destination, it won't remember that destination when the unit is subsequently powered up. However, if you have an orderly shutdown, the destination is stored in flash for the next power up. If you set your configuration to "start where I left off" on power up, there it will be.

Fragmented memory isn't a huge issue with flash as it once was with mag drives since it's a matter of memory addressing vs. physical movement. Those address lines can be flopped around a whole lot faster than Mr. Bernoulli could have ever imagined.

 

[frankxs]

As long as there's still memory left when a write occurs, you've got enough. And believe me, there's nothing you're going to do from the keypad that will come close to adding a 30MB load to the unit. I have a list of about 1200 geocaching waypoints with descriptive info for each that takes up only 90KB.

Writes don't occur immediately for every task, either. Many are held in DRAM and deferred until the unit is "shut down". For example, if the unit crashes/reboots while you're navigating to a destination, it won't remember that destination when the unit is subsequently powered up. However, if you have an orderly shutdown, the destination is stored in flash for the next power up. If you set your configuration to "start where I left off" on power up, there it will be.

Fragmented memory isn't a huge issue with flash as it once was with mag drives since it's a matter of memory addressing vs. physical movement. Those address lines can be flopped around a whole lot faster than Mr. Bernoulli could have ever imagined.

Thanks. Good point about the writes that occur at shutdown. Also good point about how it's almost impossible to add much data from a keyboard (or user input). I just wanted to hear from long-time TT users and if they had ever experienced a crash or slow performance due to full Internal memory. BTW, maybe you meant "Newton"? Anyway, I appreciate your comments.

-Frank

 

[Ray Dingli]

With standard spinning disks, they are generally significantly slower when full or almost full. I think this is primarily due to the mechanical nature of the spinning disk and the time for the "arm" to move around to access the data. I suspect this is not true of "flash drives" like the 720's Internal Memory drive. Right?

Does anyone have any recommendations on how full is too full? Does it need "working space?" If you had, say, 30MB free, is that enough?

-Frank

no idea to your question - I am a tom tom newbie - have a three yr old tom tom one & having problems with the screen - when you try to enter a letter on the keypad the one to its left appears on the screen. is this a known tom tom issue and is it fixable?