Meltdown and Spectre vulnerabilities

I know! I know! I am so active these days in blogging! That’s because of important international and domestic events! In my 2 previous posts, I have covered 2 important things happened to me in work during these 2 days.

I’ve read more about Meltdown and Spectre vulnerabilities these days. In recent years, we had bunch of vulnerabilities in computer software industry like shellshock, Heartbleed, Grub 2 authentication bypass by pressing backspace 28 times, and last but not least and probably the most important one, a critical bug in Microsoft Windows SMB server which finally caused WannaCry. Now, it’s time to find a critical vulnerable issue in CPU hardware!

Against earlier mentioned bugs, Spectre and Meltdown vulnerabilities are hardware related ones. These kinds of bugs are very very hard to find and very very hard to fix. As people can not change all their affected hardware, we need to address these bug using operating system’s kernel. Patching kernel for addressing such bugs will complicate OS kernels more and will move bugs from hardware to software/kernel bugs.

Almost all computer guys are talking about these hot bugs and I do not want to repeat them. I am just here to conclude three things from these vulnerabilities:

  1. I’ve studied Computer Organization and Design by David A. Patterson and John L. Hennessy and Modern Operating Systems by Andrew S. Tanenbaum during last 2 years. Thanks to these scientists and my prior studies in electronic engineering technology, I can understand how such a thing is possible. I also know how hard is to discover such a bug in hardware and this can not be done by a single person, but a group of security researchers with spending years of study and research. I suggest you to take a look at these books. You will love them. I promise.
  2. I made sure that independent people can participate and have a great effect on such a important papers. Paul Kocher had a great work on Spectre and a great help to find and address  Meltdown. He cited in those papers as an independent researcher. Also, for-profit-corporations like Cyberus Technology GmbH and Rambus, Cryptography Research Division could have effect on papers.
  3. This is the first time that I see a great co-operation from German company in a very important affair in computer science.

Another power supply unit defect!

Today, Mehrnoosh brought her PC to the company and asked me to take a look at it. She said, she can not turn her PC on anymore.

The first thing I did was plugging it to electricity and making sure its power cord is OK! Then opened  the case doors and detached power supply unit connectors from motherboard, HDD and ODD. Then tried to connect green wire to black wire via a jumper to make sure power button is not the problem. I realized power supply is not going to be turned on by connecting green wire to black ones. So, power supply is damaged (it’s possible that power button has problem too). We completely detached power supply and replaced it by a spare power supply. Everything was OK and operating system was booted. So, the only problem was the power supply itself. As, I know by experience, a lot of power supply makers use poor capacitors in their products, so they will blow up after a few years of working.

I opened the power supply ans saw I was right! Some of capacitors were blew up!

The main problem was related to a 10 volt/2200 micro Farad capacitor, so I suggested Mehrnoosh to replace it with a 16 volt or more, same capacity electrolytic (preferably, solid) capacitor or buy a reliable PSU like Cooler Master products. She chose the second option!

Disassemble Lenovo IdeaPad 300

Last day, Farshid asked me to take a look at Lenovo IdeaPad 300 that Mr. Ahmadi complaint he can not turn it on. Farshid spent some time on it and finally asked me for some help. I checked items Farshid has just thought may cause the problem. I thought it maybe something related to the software so we had to reboot it but as laptop was fully charged and waiting for depleting the battery might take a long time (because the device does not use battery. Finally as the battery is not removable in Ideapad 300, we decided to disassemble it! At this time Mehrnoosh joint us to see what is happening there. As I studied electronics and I had some prior experience on disassembling and mending devices, I started the work! Disassembling was somewhat easy. It got back to old days of hardware and electronic.


P.S. : The problem was something more serious, so we decided to sent it to one of Lenovo’s authorized repair shops.

What are the minimum features of a 2017 smartphone?

Before installing LineageOMS 14.1 on my Sony Xperia M phone, I decided to buy a new smartphone. In one side, I didn’t want to spend a lot of money for purchasing a high end smart phone. On the other side, I wanted to buy something had could be updatable for at least 2 years, so I can focus on other things rather than finding custom ROMs for updating the OS. Apple’s iPhones are very high quality smartphones, but they are very very expensive. I was thought about iPhone SE because its OS is iOS and it was not as expensive as iPhone 7 or even iPhone 6S. The only problem with iPhone SE was its front camera with 1.2 mega pixel camera. I continued googling but this time, looking for Android phones with minimum features I just like. Here are most important ones:

LED technology display

LCD era is over. Now, we are in LED displays. In a short sentence, LCD displays need a backlight and are not colorful. Colors are generated after passing light from red, green, blue filters. Read more about disadvantages of LCD. LEDs are naturally colorful (using different semi-conductors) and do not need any backlight. So they are brighter, use less energy and have vivid colors. AMOLEDs will be dominant display technology very soon. Sony, LG, HTC, Huawei and others awaited for Apple to introduce an iPhone with AMOLED display to follow its way and build their new display with AMOLED display.s


These days, mobile phone manufacturers try to use efficient ways of notifying people. From substituting traditional LED notification light to use second display like what LG V20 has. I think the most efficient way for notification is using AOD (Always On Display) like what Samsung is using on its flagship smartphones and even mid range phones like Galaxy A5 2017.

Finger print sensor

Take much time to unlock your smartphone? Do not want everybody to watch your password or pattern? Finger print sensor is a good way to achieve this.

Fast Charge

Our usage of smartphone is increasing. So better to buy a smartphone with fast charge feature.

USB type C

Everybody in this world have problem with attaching USB (Type A, B, MicroUSB and all other types except type C) cable and gadgets. It is not reversible and we almost attach 50% of times in reverse direction. It is an annoyable thing and in worst case, you may damage the port. Reversible USB Type C is the solution!

Good selfie camera

Go to trip and hard to find someone to take a good and sharp of you? You have to buy a smartphone with a good selfie camera. It’s better to have front flash, but it’s not a big deal.


At last but not least, price is an important item. You can use your smartphone maximum 3 years (if your phone is a flagship and 2 years if your phone is a mid level phone) if you want to update to the latest updates. So, I recommend you to not spend a lot of money for purchasing a very high end phone.

My suggestion

With this and that, in Aug 2017, my recommended mobile phones is Samsung Galaxy C5 pro. Its main features are 5.2″ display, Super AMOLED full HD display,  4GB of RAM, 64GB of internal storage, USB type C, AOD, fast charge, finger print sensor, 16 M pixel f 1.9 rear and front camera and Android Nougat with a price about 350 USD on Amazon.

If you can ignore using LED display,  Huawei Nova 2 plus can be an alternate.

Long USB charger cable

The problem is, my original Sony micro USB to USB 2.0 is very short. It’s about 50 centimeters and I couldn’t work with my smartphone while it’s charging. Other than that, the cable Forough used to use for charging her Huawei work smartphone has been damaged because it is very thin and does not work properly.

I bought 2 long micro USB to USB 2.0 cables ( one is a 2 meters cable, another is a 3 meters) for Forough and myself. Although this cables has just 2 wires for charging phones and does not have data wires, but it’s OK because we just need them for charging. They used a thick plastic cover, so they could deceive me it has a thick cooper wires. But unfortunately xp-product is used a very low quality thin wires, so when you use 3 meter cable as a charge cable, your charge speed will  dramatically decrease from 1.5 hour (10-100%) to about  10 hours!

PS:  The latest photo has been taken from Mehrnoosh’s LG V20 smartphone. I’ll write my review and my criticism for her new smartphone in next posts.