segregated witness – Hardware Wallet Vulnerability Fix – Verifying Input Value

I’m confused by the proposed solution posted in the blog regarding the recent vulnerability https://blog.trezor.io/details-of-firmware-updates-for-trezor-one-version-1-9-1-and-trezor-model-t-version-2-3-1-1eba8f60f2dd?gi=504a17ecca1c

The fix is straightforward — we need to deal with Segwit transactions in the very same manner as we do with non-Segwit transactions. That means we need to require and validate the previous transactions’ UTXO amounts. That is exactly what we are introducing in firmware versions 2.3.1 and 1.9.1.

I thought the value was already required to sign a raw segwit transaction… Since the change to segwit the full value of the input was needed in order to sign the raw transaction whereas before with legacy addresses you can simply sign without the input value amount.

They basically state the same thing in the article:

This is defined in BIP-143 and one of the changes was that the amount
of the UTXO is present in the signed data. This helps significantly;
if the attacker lies about the UTXO’s amount, the signature is simply
not valid in the Bitcoin network.

I guess I need it explained to me like a child because I don’t get it, what are they checking and validating, how are they validating? Are they going back two transactions now?

macbook pro – Frequent NVRAM resetting for WIFI hardware

I have a MacBook Pro (13 “, Mid 2012) model running Mac OS 10.14.6 (Mojave). Of late I’m experiencing a lot of problems with the WIFI hardware frequently “shutting down” or going into a inoperational state. I found the fix of resetting the NVRAM working for me. But this thing is happening very frequently.

My Macbook habits : I keep opening a lot of tabs on my safari and a lot of pdfs on my Preview. I mostly keep my pro in sleep state. Rarely do I shut down! And sometimes I code. I shifted to Mojave from the prior operating system, where the problem actually initiated, thinking a software update would fix things permanently.

What I would like help on is understanding the functioning on the NVRAM:
why does the NVRAM resetting fix the WIFI?

What makes the WIFI hardware go bust again?

Is it a hardware problem,
as in my macbook is too old and needs a wifi hardware repair? If so,
then why does resetting NVRAM temporarily fix things?

I’d like some understanding to this situation I am stuck in!

mining hardware – Higher cost running Antminer S9 w/ APW3++ when running at 220v?

The AntMiner S9i 13.5 TH/sec model requires 101.5 Amps DC. Since power (watts) is equal to voltage multiplied by amps, the total power consumed by the AntMiner is 1218 watts (+/- 10%). Note, this is regardless of whether that’s AC or DC, and regardless of voltage. 1218 watts is 1218 watts, or if you run it for an hour, 1.218 KW/hr. In my case, that works out to about $54.44 USD per month, regardless of voltage.

The APW3++ power supply doesn’t care what A/C voltage you supply it with, in the range of 100 to 240 volts, it simply converts that into the required amps output in DC. If the AntMiner is puling 1218 watts, that will translate (at 93% efficiency) to 11.85 amps at 110 volts, or 5.43 amps at 240 volts. Running two AntMiner S9s on a single 120 volt 15 amp circuit is pushing the boundaries of safe operation. You should ensure you only run a single AntMiner per 110 volt circuit, unless those circuits are fed with 12 gauge or lower wiring, and are rated for at least 20 amps.

Attaching the APW3++ power supplies to 240 volt circuits simply means you are pulling less amps per hour than if it is connected to a 120 volt circuit, and you can connect two, or possibly three, AntMiners to a single 240 volt circuit.

So, to answer your question, no, it’s not more expensive to run at 240 volts than 120 volts. In fact, due to power efficiency, it’s probably very slightly cheaper to run at 240 volts.

20.04 – Hardware compatibility with Dell notebook

Ubuntu,

I recently tried to install Ubuntu 20.04 LTS on a Dell notebook and the installation never completed.

I had a problem with Ubuntu 19.10 (Eoan Ermine). After installing, do not leave the login screen. Only Ubuntu 18.04.4 LTS (Bionic Beaver) works.

I did not find the model of the notebook at https://certification.ubuntu.com/desktop. I wonder if this hardware is really not supported.

Below a details of the hardware.

The notebook is Dell Inspiron 15 Gaming 7567.

Processor
Intel® Core™ i7-7700HQ CPU @ 2.80GHz

Chipset

Intel® 100 Series/C230 Series Chipset Family

Graphics

NVIDIA GeForce GTX 1050 Ti

Intel® HD Graphics 630

Memory
8 GB

hardware – 2017 MacBook Pro Battery Not Charging

Having a problem with my recently purchased refurbished 2017 15″ MacBook Pro. Yesterday it suddenly shut down and after rebooting, I noticed the battery was at 1% despite being plugged in. Now if it gets unplugged, the system shuts down instantly. When I click on the battery icon in the menu bar, it says:

  • Battery Is Not Charging
  • Power Source: Power Adapter

No warning about servicing or replacing the battery. The interesting part comes up when I check the system information. Under power, it lists:

Charge Information:

  • Charge Remaining (mAh): 0
  • Fully Charged: Yes
  • Charging: No
  • Full Charge Capacity (mAh): 6736

Health Information:

  • Cycle Count: 4
  • Battery Installed: Yes
  • Amperage (mA): 0
  • Voltage (mV): 12904

The fact that the charge remaining is 0 but that it’s still thinks it fully charged leaves me to believe that this is what is preventing it from charging properly. I’ve Googled the problem pretty thoroughly but everyone I’ve come across with a similar issue has Charge Remaining: 0/Fully Charged: No.

So far I have tried resetting SMC, different outlets & leaving it unplugged with the clamshell open all night in an attempt to fully drain the battery. Does anyone have any other suggestions short of taking it in for servicing? I bought this thing like 4 weeks ago so I’d rather not have to spend more cash on it already. According to the Apple website, this computer has had the battery recall issue taken care of already. Could the new one be calibrated incorrectly?

System Specs:

  • MacBook Pro (15-inch, 2017)
  • 2.9 GHz Quad-Core Intel Core i7
  • 16 GB 2133 MHz LPDDR3
  • Intel HD Graphics 630 1536 MB

Thanks in advance for any help you might be able to offer

visual studio code – como fazer a depuração de hardware no vscode para flutter?

Já com o dispositivo no modo dev ativo, conectado ao adb…

Quando executo o f5 no vscode a ide retorna para mim:

Your launch config references a program that does not exist. If you have problems launching, check the “program” field in your “.vscode/launch.json” file

devo estar pulando alguma etapa do processo… como faço para rodar as minhas aplicações no meu dispositivo?

com o codigo padrão no Dart é possivel executar uma aplicação simples… apenas quero testar o debug sem emulador.

How do I check the hardware of my iMac?

I have a late 2012 iMac that I suspect has something failing in terms of disk or USB.

This is what is happening:

  1. Some programs freeze from times to times. Once that happens, there is no way for the program to run again. Just a restart of the iMac will solve that.
  2. WHen #1 happens the computer fails to shutdown. I have to force shutdown.
  3. I have 4 USB external drives connected to a USB HUB that is connected to the Mac. From times to times, all these disks disconnect.
  4. I am unable to boot in diagnostic mode. Restarting the computer with D pressed makes the computer reach a white page that does not go anywhere. Restarting the computer with Option D (diagnostics over internet) shows a screen that appears to be loading something. It takes centuries for the progress bar to advance 1/100 of a pixel. For the pace of that progress bar I estimate 8 hours just to show the diagnostic screen, if anything is loading at all.
  5. Restarting the computer in recovery mode over internet, shows the spinning globe. Same thing, slow as hell. I estimate 2h just to show the recovery screen.

I am suspecting the disk is failing. That late 2012 iMac uses a spinning disk that I suspect is going bad. All fsck to that disk shows two, what I think is bad sectors. The SMART screen shows nothing wrong with the disk.

But, running smartctl shows me this for the Macintosh HD.

=== START OF INFORMATION SECTION ===
Device Model:     APPLE HDD WDC WD10EALX-408EA0
Firmware Version: 07.01D03
User Capacity:    1,000,204,886,016 bytes (1.00 TB)
Sector Size:      512 bytes logical/physical
Rotation Rate:    7200 rpm
Device is:        Not in smartctl database (for details use: -P showall)
ATA Version is:   ATA8-ACS (minor revision not indicated)
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Thu May 28 00:34:24 2020 WEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x82) Offline data collection activity
                    was completed without error.
                    Auto Offline Data Collection: Enabled.
Self-test execution status:      (   0) The previous self-test routine completed
                    without error or no self-test has ever 
                    been run.
Total time to complete Offline 
data collection:        (16800) seconds.
Offline data collection
capabilities:            (0x7b) SMART execute Offline immediate.
                    Auto Offline data collection on/off support.
                    Suspend Offline collection upon new
                    command.
                    Offline surface scan supported.
                    Self-test supported.
                    Conveyance Self-test supported.
                    Selective Self-test supported.
SMART capabilities:            (0x0003) Saves SMART data before entering
                    power-saving mode.
                    Supports SMART auto save timer.
Error logging capability:        (0x01) Error logging supported.
                    General Purpose Logging supported.
Short self-test routine 
recommended polling time:    (   2) minutes.
Extended self-test routine
recommended polling time:    ( 194) minutes.
Conveyance self-test routine
recommended polling time:    (   5) minutes.
SCT capabilities:          (0xb037) SCT Status supported.
                    SCT Feature Control supported.
                    SCT Data Table supported.

SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x002f   200   200   051    Pre-fail  Always       -       1
  3 Spin_Up_Time            0x0027   181   173   021    Pre-fail  Always       -       3933
  4 Start_Stop_Count        0x0032   091   091   000    Old_age   Always       -       9305
  5 Reallocated_Sector_Ct   0x0033   200   200   140    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x002e   100   253   000    Old_age   Always       -       0
  9 Power_On_Hours          0x0032   065   065   000    Old_age   Always       -       26100
 10 Spin_Retry_Count        0x0032   100   100   000    Old_age   Always       -       0
 11 Calibration_Retry_Count 0x0032   100   100   000    Old_age   Always       -       0
 12 Power_Cycle_Count       0x0032   091   091   000    Old_age   Always       -       9284
192 Power-Off_Retract_Count 0x0032   192   192   000    Old_age   Always       -       6185
193 Load_Cycle_Count        0x0032   199   199   000    Old_age   Always       -       3115
194 Temperature_Celsius     0x0022   095   093   000    Old_age   Always       -       52
195 Hardware_ECC_Recovered  0x0036   200   200   000    Old_age   Always       -       0
196 Reallocated_Event_Count 0x0032   200   200   000    Old_age   Always       -       0
197 Current_Pending_Sector  0x0032   200   200   000    Old_age   Always       -       0
198 Offline_Uncorrectable   0x0030   200   200   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x0032   200   200   000    Old_age   Always       -       0
200 Multi_Zone_Error_Rate   0x0008   200   200   000    Old_age   Offline      -       18

SMART Error Log Version: 1
No Errors Logged

SMART Self-test log structure revision number 1
Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Short offline       Aborted by host               10%     21652         -

SMART Selective self-test log data structure revision number 1
 SPAN  MIN_LBA  MAX_LBA  CURRENT_TEST_STATUS
    1        0        0  Not_testing
    2        0        0  Not_testing
    3        0        0  Not_testing
    4        0        0  Not_testing
    5        0        0  Not_testing
Selective self-test flags (0x0):
  After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.

and for the Macintosh HD - Data:

=== START OF INFORMATION SECTION ===
Device Model:     APPLE HDD WDC WD10EALX-408EA0
Firmware Version: 07.01D03
User Capacity:    1,000,204,886,016 bytes (1.00 TB)
Sector Size:      512 bytes logical/physical
Rotation Rate:    7200 rpm
Device is:        Not in smartctl database (for details use: -P showall)
ATA Version is:   ATA8-ACS (minor revision not indicated)
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Thu May 28 00:33:11 2020 WEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x82) Offline data collection activity
                    was completed without error.
                    Auto Offline Data Collection: Enabled.
Self-test execution status:      (   0) The previous self-test routine completed
                    without error or no self-test has ever 
                    been run.
Total time to complete Offline 
data collection:        (16800) seconds.
Offline data collection
capabilities:            (0x7b) SMART execute Offline immediate.
                    Auto Offline data collection on/off support.
                    Suspend Offline collection upon new
                    command.
                    Offline surface scan supported.
                    Self-test supported.
                    Conveyance Self-test supported.
                    Selective Self-test supported.
SMART capabilities:            (0x0003) Saves SMART data before entering
                    power-saving mode.
                    Supports SMART auto save timer.
Error logging capability:        (0x01) Error logging supported.
                    General Purpose Logging supported.
Short self-test routine 
recommended polling time:    (   2) minutes.
Extended self-test routine
recommended polling time:    ( 194) minutes.
Conveyance self-test routine
recommended polling time:    (   5) minutes.
SCT capabilities:          (0xb037) SCT Status supported.
                    SCT Feature Control supported.
                    SCT Data Table supported.

SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x002f   200   200   051    Pre-fail  Always       -       1
  3 Spin_Up_Time            0x0027   181   173   021    Pre-fail  Always       -       3933
  4 Start_Stop_Count        0x0032   091   091   000    Old_age   Always       -       9305
  5 Reallocated_Sector_Ct   0x0033   200   200   140    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x002e   100   253   000    Old_age   Always       -       0
  9 Power_On_Hours          0x0032   065   065   000    Old_age   Always       -       26100
 10 Spin_Retry_Count        0x0032   100   100   000    Old_age   Always       -       0
 11 Calibration_Retry_Count 0x0032   100   100   000    Old_age   Always       -       0
 12 Power_Cycle_Count       0x0032   091   091   000    Old_age   Always       -       9284
192 Power-Off_Retract_Count 0x0032   192   192   000    Old_age   Always       -       6185
193 Load_Cycle_Count        0x0032   199   199   000    Old_age   Always       -       3115
194 Temperature_Celsius     0x0022   095   093   000    Old_age   Always       -       52
195 Hardware_ECC_Recovered  0x0036   200   200   000    Old_age   Always       -       0
196 Reallocated_Event_Count 0x0032   200   200   000    Old_age   Always       -       0
197 Current_Pending_Sector  0x0032   200   200   000    Old_age   Always       -       0
198 Offline_Uncorrectable   0x0030   200   200   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x0032   200   200   000    Old_age   Always       -       0
200 Multi_Zone_Error_Rate   0x0008   200   200   000    Old_age   Offline      -       18

SMART Error Log Version: 1
No Errors Logged

SMART Self-test log structure revision number 1
Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Short offline       Aborted by host               10%     21652         -

SMART Selective self-test log data structure revision number 1
 SPAN  MIN_LBA  MAX_LBA  CURRENT_TEST_STATUS
    1        0        0  Not_testing
    2        0        0  Not_testing
    3        0        0  Not_testing
    4        0        0  Not_testing
    5        0        0  Not_testing
Selective self-test flags (0x0):
  After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.

But I am not sure if I understand these enigmatic reports.

Do these numbers make sense as a failing disk?

Are cheap 2.5″ external hard disks constrained to Exfat and incompatible with Time Machine? Is this a physical limitation / hardware issue?

I bought two 2TB 2.5″ external HDDs that came with the following warning message in a Readme file contained in the drives.

“The drive can only be formatted with Exfat and cannot be formatted in other for mats, suchas NTFS, FAT32, FAT. Otherwise it will cause the hard drive t be unusable!
This hard disk is only suitable for windows system and XP system not suitable for PS4, xbox macbook,tv, etc.
The disk needs to be inserted into the USB interface of the device’s motherboard. If the transfer method is used, there may be insufficient power supply to the disk.”

Both drives appeared to work straight out of the box. However, I got errors when trying to partition them (I use a MBP, mid-2015 Retina, MacOS 10.3.3). Now one of the external drives has become unusable. So…I’m guessing this could be because these are cheap no-brand drives which I ordered from China, similar to these:

And I’m guessing the manufacturer has assembled them or configured them in this way (limited to Exfat) in order to cut costs. My questions are:

  1. Why/how an external drive can be manufactured to be permanently only Exfat?
  2. Is this a hardware constraint or physical limitation imposed by the manufacturer or by the USB to SATA bridge used?
  3. Is there a way to overcome this so that I can use them for Time Machine backups?…Has anyone been succesful in backing up with Time Machine on these types of 2.5″ external hard drives?

From the Terminal query below, it appears that the drive is a JMicron device. I’ve now got in touch with JMicron and waiting to hear back (will post updates here). In the meantime, if anyone can shed any light and answer/respond to any of the above questions I’d very much appreciate it.

diskutil info /dev/disk1:

   Device Identifier:        disk1
   Device Node:              /dev/disk1
   Part of Whole:            disk1
   Device / Media Name:      JMicron Generic Media

   Volume Name:              Not applicable (no file system)

   Mounted:                  Not applicable (no file system)

   File System:              None

   Content (IOContent):      FDisk_partition_scheme
   OS Can Be Installed:      No
   Media Type:               Generic
   Protocol:                 USB
   SMART Status:             Not Supported

   Total Size:               2.0 TB (2000398934016 Bytes) (exactly 3907029168 512-Byte-Units)
   Volume Free Space:        Not applicable (no file system)
   Device Block Size:        512 Bytes

   Read-Only Media:          No
   Read-Only Volume:         Not applicable (no file system)
   Ejectable:                Yes

   Whole:                    Yes
   Internal:                 No
   OS 9 Drivers:             No
   Low Level Format:         Not supported

Below is a screenshot showing the readme file and the warning contained in it.

enter image description here

NB. Question asked earlier to try and restore the unusable drive here Unusable 2.5″ external HDD. Partition failed with the error -69760: Unable to write to the last block of the device. Exfat only? Repairable?).

hardware – Can I access both cameras, wide and normal at the same time?

Some smartphones have two cameras, working together as one implementing different parts of the zoom range.

Is it possible to use both of them at the same time?

With both at the same time, I do not necessarily mean reading the frames at the same time synchronously, reading both with 30 Hz from different threads would be great.

A problem could be if a camera needs to be initialized somehow, and only one can be in the active state at a time.

memory hardware – Hard Drive Seek Time using FIFO, SSF, SCAN

A hard disk spins at 6000 rpm (revolutions per minute), and it takes 100 μs (on average) for the head to traverse one track. Consider the following sequence of disk track requests: 27, 129, 110, 186, 147, 41, 10, 64, 120. Assume that initially the head is at track 30 and is moving in the direction of decreasing track numbers. Compute the time it takes to serve the requests using (1) FIFO, (2) SSF (Shortest-Seek First), (3) SCAN.

I understand the difference between the different algorithms and I generally get how to calculate it.

My questions is, when I calculate the Average rotational time, i.e. (60/6000) / 2 = 5ms, do I need to multiply this by the number of tracks moved?

My FIFO calculation as an example:

(3+102+19+76+39+106+31+54+56) * (5ms + 0.1ms) = 2478.6ms

I add up the number of tracks moved and multiply this by the average rotational time + the time it takes to traverse each track.

Is this approach correct?

Thank you