Debian 11, UEFI, and non-free wireless driver

 This is not trivial. I want to dual boot my Windows with Debian 11.

To solve the UEFI problem you must boot the installer in UEFI mode. You should see the UEFI information appears in the installer splash screen. If you boot the installer in ordinary/legacy mode, be prepare for the problems. The problem I encountered was unable to install grub. 

I boot the installer in UEFI mode from the option from windows, it run smoothly. Magically everything went fine.

Non-free wireless driver must be copied into a drive in a deb file. Plug the drive at the same time as the installer. I've never succeeded this step by hot plugging the drive during installation.

voila.

Koleksi berita obat COVID-19

12 Mei 2022: Pandemi sepertinya telah berakhir, berikut arsip perkembangan pembuatan obatnya. Saat ini telah ada Paxlovid dan Molnupiravir sebagai obat yang diformulasikan untuk Covid-19.

Arsip:

Berikut ini list berita yg berkaitan dengan obat COVID-19, semoga meningkatkan optimisme kita untuk menghadapi virus corona. Para peneliti telah dan terus bekerja keras untuk menemukan obat yang tepat, hal ini bisa dilihat dari perkembangan yang cepat dari waktu dipublikasikannya hasil penelitian yang cuma berjangka waktu satu bulan.

Setelah satu tahun banyak obat yang diresepkan secara darurat atau bahkan dalam tahapan uji klinis untuk mengobati Covid, namun sampai saat ini obat Covid masih belum ada.

1. Paxlovid
• Produk Pfizer yang dikembangkan untuk covid
• Mengandung nirmatrelvir dan ritonavir.
• Nirmatrelvir untuk menghambat protein SARS-COV-2 sehingga tidak dapat melakukan replikasi
• Ritonavir untuk menjaga nirmatrelvir agar tetap ada di dalam tubuh dalam konsentrasi tinggi
  
2. Molnupiravir
• Antivirus dari Merck yang dikembangkan khusus untuk corona virus
  
3. Favipiravir
• Antivirus; menghambat replikasi virus
• Perawatan influenza dari Jepang
• Merk: Avigan
• Status: diresepkan di Indonesia
  
4. Oseltamivir
• Antivirus; menghambat replikasi virus
• Perawatan influenza dari Jepang
• Merk: Tamiflu
• Status: diresepkan di Indonesia
  
5. Remdesivir
• Antivirus; menghambat replikasi virus
• Perawatan hepatitis C dan hRSV (virus pada saluran pernafasan)
  
• Merk: Covifor, Veklury
• Status: diresepkan di Indonesia
6. Tocilizumab
• Immunosuppresant, Antibody monoclonal: mengatasi terjadinya cytokine storm
  
• Perawatan rheumatoid arthritis
• Merk: Actemra
• Status: diresepkan di Indonesia
7. IVIG/IGIV 
• Antibody
• Merk: Privigen, Gamaras
• Status: diresepkan di Indonesia
8. Methisoprinol
• Antivirus
  
• Obat Herpes
• Status: diresepkan di Indonesia
9. Lopinavir + Ritonavir
• Antivirus
  
• Obat HIV
• Merk: Lopivia
• Status: diresepkan di Indonesia
10. Azythromicyn
• Antibiotik
• Status: diresepkan di Indonesia
11. Ivermectin
• Obat Cacing untuk binatang ternak
• Status: diresepkan di Indonesia
12. Dexamethasone
    
    • Status sudah terbukti dengan uji klinis pada pasien di inggris
    • Referensi https://www.bbc.com/news/health-53061281 (Michelle Roberts, 16 Juni 2020)
    • Cara kerja dijelaskan di sini https://medium.com/@shinjieyong/biology-of-dexamethasone-the-first-lifesaving-drug-for-covid-19-357ed9daaf7a
13. Obat pengencer darah
    
    • Cara kerja dengan membuat darah encer diharapkan bisa mencegah terjadinya penggumpalan darah yang menyebabkan stroke.
    • Referensi https://www.telegraph.co.uk/news/2020/05/16/blood-thinning-drugs-can-help-save-covid-19-patients-lives/  (Tom Morgan dan Edward Malnick, 16 Mei 2020)
14. Colchicine (Recolfar)
    
    • Status: masih diuji di tikus.
    • Merupakan obat gout, asam urat.
    • Cara kerja dengan menghambat pengeluaran alpha defensin yang menyebabkan terjadinya penggumpalan darah (blood clot) yang dapat menyebabkan stroke.
    • Diklaim lebih tepat dibandingkan obat-obatan pengencer darah
    • Referensi https://www.jpost.com/health-science/hadassah-doctors-crack-the-cause-of-fatal-corona-blood-clots-631681 (MAAYAN JAFFE-HOFFMAN, 16 Juni 2020)

Interval arithmetic with mpfi

Interval arithmetic is a mature field in computer science that was conceived in the 50s or 60s. Mostly it was used to ensure the precision of floating point numbers, i.e. a floating point number's possible max and min value fall into certain precision. E.g. 3.13< pi< 3.15

Problem: having an f(x), we want to find the max and min of f(x) for x between x1 and x2.

I'm trying to solve this problem with mpfi library:

• libmpfi-dev - multiple precision floating-point interval computation library
• libmpfi0 - multiple precision floating-point interval computation library

Here is the code for f(x)=x^3 with x1=-4 and x2=3:

 
#include "stdio.h"
#include "mpfi.h"
#include "mpfi_io.h"

int main(int argc, char** argv) {
  mpfi_t x, fx;

  mpfi_init(x);
  mpfi_init(fx);
  mpfi_interv_si(x, -4, 3);

  //fx = x*x*x
  mpfi_mul(fx, x, x); //fx = x*x
  mpfi_mul(fx, fx, x); //fx = fx*x
  mpfi_out_str(stdout, 10, 2, fx); printf("\n");
  mpfi_clear(x);
  mpfi_clear(fx);
  return 0;
}

Compilation:

 $ gcc -lmpfi test.c
$ ./a.out
[-6.4e1,4.8e1]

The result is min f(x)= -64 and max f(x)= 48 for x1=-4 and x2=3

Cheap Class D audio amplifier experiments

I have a nice vintage micro sound system. It can easily accept any audio signal from my gadgets, but it consumes around 60W of power. So lets try to make a smaller carbon footage :D. I tried class D amps to drive the speakers. I did two experiments:

1. 12 Volt amp
The setup was very simple. Audio outputs from a gadget went to amp line-in. But put a variable resistor as the volume control, between the gadget audio-out and the amp's line-in. It should be a stereo one. I tried with 12V unused power supply from old networking equipment, it worked. It also worked with a 9V power supply that usually comes with todays network router.
It worked fine with phone, but there was severe hums and buzz with laptop headphone port. I suspected the problem was the connector. I used a 4-ports audio connector that usually comes with a smart phone; 2 ports for L/R channel, 1 port for microphone and the last port for the ground.
Apparently the audio port on computer didn't connect the ground correctly. The ground connector might be connected into the microphone port, thus leaved the ground unconnected. Therefore it sounded terrible,
the audio signal was very small compared to the noise. The solution was simple, just shorted the microphone port to the ground port.
However before I tried the solution, the amp was already damaged. So then I tried with the second experiment.

2. 5 Volt amp
Still same setup as the previous one, but the power supply is given from USB. Nice, no need a dedicated power supply and USB is ubquitous. I use my laptop USB to power the amp.

Observations:
It sounds rather vintage, closer to crispy sound of tube lamp amp, than deep sub wooferish sound of modern audio system. So? There is a simple rule for a good audio system, it should reproduce sound as closer as the original, a sub woofer definitely distort the original sound, thus I guess I can consider my D class amp setup sounds good.

HP printer driver in linux vs windows

I had problem with my HP deskjet 1000 on linux. As usual the cartridge was injected. I tried to print something but there was no response, neither error message nor mechanical movement. Then I switched into windows XP to see if there was anything wrong with my linux configuration. Voila, the driver gave an error message, the cartridge was not configured for this printer. Fine, a message at least, don't know whether it is correct or not. update: It turns out that the message was correct, the printer works perfectly after I change the cartridge!
Conclusion: HP still gives windows better driver, even an old OS such as XP.

incorrect acrobat reader font in linux

If your acroread doesn't render some fonts correctly try to install this package:

ttf-mscorefonts-installer

During its installation it will download and install the fonts necessary to render the pdf correctly.

command abbreviation in gnuplot

Basically it can be anything, as long as not conflicting with others, for example:

• filledcurves; filledcu
• transparent; trans trasp transpa
• using; u
• title; t, ti
• solid; sol, soli
• closed; clo, clos

Funny eh?