I will be running my applet on almost all the browsers for nearly minimum of 14hrs will that cause the browser to crash or hang.My applet will basiclly upload a file to remote server via ftp.
My applet size is about 1.5mb.
Best Regards,
Sagar
There's no reason the Applet or the browser should crash if your Applet doesn't allocate too much memory. Standard Java heap size is 64Mb so its quite comfortable. Moreover, your application seems to be streaming content and should not retain it in the memory. As for the size of the Applet itself, 1.5Mb is totally OK.
That being said, I would recommend going to a webstart application instead of Applets, because, well, I've had too many problems with Applets. Plugins installations, security constraints, etc... I try to avoid this technology whenever possible.
Related
A lot of literature that I stumbled upon referred TrustZone as a mechanism that facilitates Secure Boot (as can be seen here, and a lot more).
To my knowledge, Secure Boot operates this way:
"Root-of-Trust verifies img1 verifies img2 ..."
So in case the chip is booting from a ROM that verifies the first image which resides in a flash memory, what added value do I get by using TrustZone?
It seems to me that TrustZone cannot provide Secure Boot if there is no ROM Root-of-Trust to the system, because it can only isolate RAM memory and not flash, so during run-time, if the non-trusted OS is compromised, it has no way of protecting its own flash from being rewritten.
Am I missing something here?
So in case the chip is booting from a ROM that verifies the first image which resides in a flash memory, what added value do I get by using TrustZone?
Secure boot and TrustZone are separate features/functions. They often work together. Things will always depend on your threat model and system design/requirements. Ie, does an attacker have physical access to a device, etc.
If you have an image in flash and someone can re-write flash, it may be the case that a system is 'OK' if the boot fails. Ie, someone can not re-program the flash and have a user think the software is legitimate. In this case, you can allow the untrusted OS access to the flash. If the image is re-written the secure boot will fail and an attacker can not present a trojan image.
Am i missing something here?
If your system fails if some one can stop the system from booting, then you need to assign the flash controller to secure memory and only allow access to the flash via controlled channels between worlds. In this design/requirement, secure boot might not really do much as you are trying to construct the system to not run un-authorized software.
This is probably next to impossible if an attacker has physical access. They can disassemble the device and re-program flash by removing, external programming and reinstalling the chip. Also, an attacker can swap the device with some mocked-up trojan device that doesn't even have the same CPU but just an external appearance and similar behaviour.
If the first case is acceptable (rogue code reprogramming flash, but not bootable), then you have designs/requirements where the in-memory code can not compromise functionality of the running system. Ie, you may not want this code to grab passwords, etc. So TrustZone and secure boot work together for a lot of cases. It is entirely possible to find some model that works with only one. It is probably more common that you need both and don't understand all threats.
Pretty sure TrustZone can isolate flash depending on the vendor's implementation of the Secure Configuration Register(SCR)
Note this is with regards to TrustZone-M(TrustZone for Cortex-M architecture) which may not be what you are looking for.
I'm trying to figure out where my memory leak is coming from since lately i'm experiencing a lot of performance drop when just opening a new tab on my browser FireFox ver.51
Just to be sure I've disabled all non-Microsoft startup services in msconfig even after reboot it still gets stuck on this.
Looking up on the vendors updates for this machine then it would be up to date on the drivers, i do occasionally check for Intel Chipset and onboard Graphics drivers (stable versions only) myself that are a few years newer then the vendor.
MS Resource monitor
MS Taskmgr Perfomance monitor
In the Taskmgr Performance monitor you can see I'm barely using any CPU and I/O leaving out any form of I/O wait issues due to swapping.
When looking in the Resource monitor actual physical RAM in is about 6.3GB while Cached is only 1.6GB making it roughly 4GB RAM missing where it's usage is coming from.
So i did do a offline MemTest (oh yes the old blue gorgeous BIOS screen) and all checks were passed, luckily it's only 8GB RAM so the downtime is manage-able ;)
Any ideas or other handy tools I can use to find the culprit?
Already fixed it, seems like my pagefile is storing too much cached memory for some reason, will look into it myself why it stores so much memory
I built a game in j2me and I have memory leak because from time to time I get out of memory exception, now I want to spot where this leak is coming from and I heard you can do it with sun's wireless tool kit. Can someone explain me exactly what is this wireless tool kit, how I install it and how to use it in-order to find memory leaks ? Thanks in advance !
After you download wtk,Go to \bin\utilsw.exe.Under Utilities you will see "Memory monitor".Here you can graphically view app memory/RAM usage.
I do not know oracle sdk 3.4, but in wtk2 memory monitor was only partially useful for finding memory leaks, because it only shows how many (and which) objects are live, but not where they are referenced from. So it takes a review of corresponding piece of code.
Memory leaks are easier to find with a java profiler. You need to get one that suits you (I prefer YourKit, but it is commercial product with a trial period), modify emulator's command line in order to allow the profiler to connect (that should be covered by profiler's documentation, it is basically about adding -agentlib or -Xrun... option) to it, and do actual profiling (every profiler comes with a guide of how to do it).
am new in iphone technology i just wanted to know what is the memory that ios4 occupies in the iphone, i have read that i phone 4 has 512MB of RAM and in wiki i read that ios uses 500MB of ram so am bit confused like if it uses 500MB of ram then it leaves only 12MB free memory space for third party app, please help me out regarding this.
Thank you
It's not something you need to worry about.
If you needed to know, the information would be available.
Write your application and, if it uses too much memory, then optimise it.
You will receive memory warnings if you start to approach the memory limit, which you can respond to appropriately.
It uses 500mb of swap space, which is space on the phone's actual storage, not RAM.
It's hard to know what is multithreaded in a browser and what isn't. It seems while a video streams or progressively downloads, it does not affect page performance, so my guess it is.
Note I'm using Flash video, but it's really about video in general. Any other tips on what else is multithreaded (image loads?) is also helpful. I know JavaScript is not, and I thought Flash wasn't but I heard somewhere that it may be (or it could be done), but I think they were not well informed.
flash wmode parameter controls which mode should be used. transparent runs in browser's application domain, and "window" runs as a separate flash player process drawing on width height and x&y specified by browser.
It's platform and implementation specific. With flash on the MacOS 64 bit (sorry I only know my win platform) flash runs in its own process, so definitely multithreaded. Chrome also runs all plugins on a separate thread.