Hotel SESIL

Location: С.Амбарцумяна 26/4 Gyumri, Gyumri, am

Star Rating: 9.8 Stars

Property Type: Hotels

About this Property

Important Information

Policies

Check-in: 01:00 PM - 12:00 AM

Check-out: 12:00 PM

Amenities & Facilities

• Offsite parking discounted rates available
• Parking
• Non-smoking rooms
• Air conditioning
• Room service
• Family rooms
• Express check-in/check-out
• Soundproof rooms
• Non-smoking throughout
• Shared lounge/TV area
• Shared kitchen
• Staff adhere to local safety protocols
• Guest rooms disinfected between stays
• Cleaning standards that are effective against Coronavirus
• Physical distancing rules followed
• Hand sanitizer in guest room and key areas
• First aid kit available
• Sanitized tableware & silverware
• Guests can opt-out any cleaning services during stay
• Shared stationery like menus, pens are removed
• Guest room sealed after cleaning
• Physical distancing in dining areas
• CCTV outside property
• Process in place to check health of guests
• 24-hour security
• Delivered food - securely covered
• Front desk (limited hours)
• Express check-in
• Free wired internet
• Offsite parking discounted rates available
• Internet access
• Housekeeping on request

Rooms Available

• Budget Double or Twin Room

  Featuring free toiletries, this twin/double room includes a private bathroom with a shower, a hairdryer and slippers. The air-conditioned twin/double room features a flat-screen TV with cable channels, soundproof walls, executive lounge access and a dining area. The unit has 2 beds.

  Max Occupancy: 2 (2 Adults)

  • Shower
  • Safety deposit box
  • TV
  • Air conditioning
  • Hair dryer
  • Desk
  • Private bathroom
  • Heating
  • Slippers
  • Dining area
  • Electric kettle
  • Executive lounge access
  • Wardrobe or closet
  • Dining table
  • Clothes rack
  • Toilet paper
  • Trash cans
  • Shampoo
  • Body soap
  • Socket near the bed
  • Feather pillow
  • Lockers
  • Smoke alarm
  • Carbon monoxide detector

• Classic Triple Room

  Providing free toiletries, this triple room includes a private bathroom with a shower, a hairdryer and slippers. The air-conditioned triple room provides a flat-screen TV with cable channels, soundproof walls, a dining area, a wardrobe as well as city views. The unit offers 3 beds.

  Max Occupancy: 3 (3 Adults)

  • Shower
  • Safety deposit box
  • TV
  • Air conditioning
  • Hair dryer
  • Desk
  • Toilet
  • Private bathroom
  • Heating
  • Slippers
  • Dining area
  • Electric kettle
  • Wardrobe or closet
  • Linen
  • Dining table
  • Clothes rack
  • Toilet paper
  • Child safety socket covers
  • Bottle of water
  • Trash cans
  • Shampoo
  • Body soap
  • Socket near the bed
  • Feather pillow
  • Mobile hotspot device

• Deluxe Double or Twin Room

  Offering free toiletries, this twin/double room includes a private bathroom with a shower, a hairdryer and slippers. The air-conditioned twin/double room offers a flat-screen TV with cable channels, soundproof walls, a dining area, a wardrobe as well as city views. The unit offers 2 beds.

  Max Occupancy: 2 (2 Adults)

  • Shower
  • Safety deposit box
  • TV
  • Air conditioning
  • Hair dryer
  • Desk
  • Toilet
  • Private bathroom
  • Heating
  • Slippers
  • Dining area
  • Electric kettle
  • Wardrobe or closet
  • Linen
  • Dining table
  • Clothes rack
  • Toilet paper
  • Child safety socket covers
  • Bottle of water
  • Trash cans
  • Shampoo
  • Body soap
  • Socket near the bed
  • Feather pillow
  • Mobile hotspot device

• Large Double or Twin Room

  Featuring free toiletries, this twin/double room includes a private bathroom with a shower, a hairdryer and slippers. The spacious air-conditioned twin/double room features a flat-screen TV with cable channels, soundproof walls, a dining area, a wardrobe as well as city views. The unit has 2 beds.

  Max Occupancy: 2 (2 Adults)

  • Shower
  • Safety deposit box
  • TV
  • Air conditioning
  • Hair dryer
  • Desk
  • Toilet
  • Private bathroom
  • Heating
  • Slippers
  • Dining area
  • Electric kettle
  • Wardrobe or closet
  • Linen
  • Dining table
  • Clothes rack
  • Toilet paper
  • Child safety socket covers
  • Bottle of water
  • Trash cans
  • Shampoo
  • Body soap
  • Socket near the bed
  • Feather pillow
  • Mobile hotspot device

• Double or Twin Room

  Offering free toiletries, this twin/double room includes a private bathroom with a shower, a hairdryer and slippers. The twin/double room is fitted with air conditioning, soundproof walls, a dining area as well as a wardrobe. The unit offers 2 beds.

  Max Occupancy: 2 (2 Adults)

  • Shower
  • Air conditioning
  • Hair dryer
  • Desk
  • Toilet
  • Private bathroom
  • Heating
  • Slippers
  • Dining area
  • Electric kettle
  • Wardrobe or closet
  • Linen
  • Clothes rack
  • Toilet paper
  • Child safety socket covers
  • Bottle of water
  • Trash cans
  • Shampoo
  • Body soap
  • Socket near the bed
  • Feather pillow
  • Mobile hotspot device

Guest Reviews

• Philippe (8/5): - Hotel vraiment très bien situé. Très propre et calme. On a aussi beaucoup apprécié le jovial et sympathique patron, ainsi sa femme qui se donne corps et âme pour nous servir le meilleur des petits déjeuners. Nous ne pouvons que chaleureusement recommander cet établissement.
• Edoardo (10/5): - Tutto perfetto
• Christian (10/5): Meget venlig vært. Tæt på centrum og super flot værelse. Vi havde et meget behageligt ophold. - Super flot hotel. Meget rent og pænt. Der manglede ikke noget. Jeg kunne lide alt
• maarten.vo (10/5): -
• Björn (9/5): Good choice for Gyumri - Very friendly and helpful host. Clean room, comfy beds, good breakfast. Great location. The entrance is a bit hard to find (it's at the back of the building behind the toy shop).
• Sucur (9/5): - Odlicna lokacija, prostrana soba, super dorucak i izvanredni domaćini
• Max (10/5): - Sehr sauberes Hotel mit einer perfekten Lage. Das Frühstück war super gut und abwechslungsreich. Der Gastgeber war außergewöhnlich nett und hilfsbereit. Das Bett war sehr bequem und auch das Bad war modern und angenehm.
• El Swiss (10/5): - Emplacement Propreté Accueil du gérant
• Svetlana (10/5): - Отличное расположение. На тихой улочке в двух минутах пешком от центра. Восхитительные завтраки. Идеальная чистота. Тишина. Огромная кухня-гостиная. В номере и на кухне есть всё. Ну и конечно сердце гостиницы-хозяин! Спасибо Вам за гостеприимство! Такого нет.
• Brett (10/5): Location, location, location! - Outstanding. Clean, safe, convenient location, wonderful breakfast REAL coffee, friendly owners. Hozo even helped me book my minibus back to Yerevan. Best accommodation in Gyumri for the price!
• Yassir (10/5): - I had a great stay at this hotel. The staff were very friendly and welcoming, the room was comfortable, and the location is close to the city center. The breakfast was also very good. I would definitely recommend it.
• Petros Michaeloudes (10/5): - The place is a small family owned hotel. Hovo, the owner and his wife are honestly the best hosts you can ask. Supplying recommendations for everything, giving you advice to go around and even sorting out bus tickets to visit Yerevan. The morning breakfast was just amazing. Cooked local delicacies from the wife at your own convenient time. I can't recommend it enough. Honestly just perfect. Nothing
• Olga (10/5): - Очень хороший отель, удобная кровать, расположение в 2 минутах ходьбы от площади. Хозяевам отдельное спасибо за гостеприимство. Было позднее заселение, дождались нас. Завтраки очень вкусные, домашние.
• OKSANA (10/5): -
• senorcafe (9/5): - The hosts were very friendly and welcoming. The room was very spacious and clean. Breakfast was outstanding - omelets, fruit, juice, assorted breads, yogurt. The hotel is just 2 minutes from the main square and is very quiet. The room only has harsh overhead lighting. There are rechargeable bedside lamps, but they barely give off any light.
• ՀԱՍՄԻԿ (9/5): Все было отлично - Комната чистая, уютная, тихая. Мне очень понравилась Завтрак не плохой.
• Perrine (10/5): - La gentillesse des hôtes, les chambres très propres et spacieuses, le super petit déjeuner Rien
• Orjana (10/5): Odlična nastanitev - Odlična lokacija, blizu glavnega trga. Osebje zelo prijazno. Obilen in zelo, zelo dober zajtr. V bližini so restavrazije z dobro hrano. Nastanitev ima veliko, opremljeno kuhinjo in lep skupnji prostor. Lastnik nam je ponudil večjo sobo za isto ceno. Lepa in velika kopalnica. Avto smo parkirali na cesti pred stavbo, ima pa tudi parkirišče za stavbo. Vhod ni z ulice ampak z zadnje strani stavbe. Radi bi dali višjo oceno od 10, ker si ta nastanitev to res zasluži. Žal nismo mogli ostati dalj časa.
• Andrey (10/5): -
• Maxim (10/5): - Спасибо за гостеприимство и радушие!! Встретимся обязательно ещё!!
• Jim (10/5): Excellent - Personnel au top! Emplacement au top! Chambres au top! Quoi de plus? Rien à dire
• Mikhail (10/5): - A family hotel. Rooms are very good and clean, owner is very helpful. Owner's wife prepares delicious breakfasts! Hotel is located in the very center of the city.
• Luca (10/5): Centralissima e pulitissima camera in centro a Gyumri - Centralissimo, a due passi dalla piazza principale, ma si parcheggia comunque facilmente. Staff gentilissimo, disponibile e comunicativo. Parlano inglese. Colazione fantastica. Camera matrimoniale spaziosissima con tavolo, sedie e divano. Bagno con doccia super. Materassi e cuscini nuovi e comodissimi. Rapporto qualità prezzo fantastico. Era tutto perfetto
• Erghena (9/5): - Чистота Единственный минус-белье очень пахнет стиральным порошком.Либо доп.полоскать либо использовать меньшее кол-во моющего средства
• Elena (10/5): -
• Jiří (10/5): -
• Svetlana (10/5): - Приятное тихое место. Нас встретили радушные хозяева. Очень хороший уютный номер, в номере все есть. Есть хорошо оборудованная кухня и нас накормили вкусным завтраком. Остались довольны.
• Tatiana (9/5): To visit Gumri and stay as at home - The hotel is located in the historical center of the city, but it is very quiet. The bed was just great, the room extremely clean and warm. The owners, a nice armenian family, were very attentive and ready to help. The breakfas was very rich and home made. No concerns.
• Vitus (10/5): -
• Hugo (10/5): prima adres voor bezichtigen stad (ook een mooie stad overigens) - Fantastische gastheer die ons oprecht verwelkomde en veel goede tips mee gaf voor het bezichtigen van de stad. Het hotel zit vlakbij het grote plein. Geweldig ontbijt ook!
• Marco (10/5): Consigliatissimo - Ottima posizione e staff gentile e ospitale, le stanze erano spaziose e pulite e la colazione era ottima. Decisamente consigliato!
• Ian (9/5): -
• Roger (10/5): - The staff went above and beyond helping me
• Anna (10/5): Bona ubicació i habitacions boniques - Les habitacions molt netes, boniques i còmodes. L'esmorzar de 10. L'Hovo i la seva dona molt atents i amables. Bona ubicació.
• Rodolfo (10/5): Estadia perfeita em tudo! - Adorei a nossa estadia em Gyumri, em todos os sentidos! A localização não podia ser melhor, mesmo à entrada da praça central da cidade. Os anfitriões foram fantásticos! Cozinharam-nos um ótimo pequeno-almoço, deram-nos dicas de onde comer uma boa comida tradicional arménia na cidade e foram muito prestáveis com todas as situações. O estacionamento é nas traseiras do edifício, mas como a porta de entrada é nas traseiras também, o carro está praticamente à porta. O quarto em si era muito confortável e limpo. Recomendo totalmente este alojamento quando visitarem Gyumri! Nada
• Ian (10/5): -
• ferenczj62 (9/5): - Nagyon kedves, udvarias vendéglátó várt minket. Ragyogó tisztaság, nemdohányzó hotel, az udvaron parkolóval. A városközpontban, mégis csendes helyen.
• JC (9/5): -
• Patricia (10/5): - -very nice owner -parking on site -excellent breakfast -nice, modern room -central location -
• Stewart (10/5): - Such lovely hosts and the room was clean and comfortable. Awesome breakfast as well!
• Stewart (10/5): -
• александра (10/5): - Отель у самом центре , супер приветливые хозяева , великолепный завтрак , чистейшие просторные номера . Рекомендую
• Guest (10/5): A very nice experience. The place is comfortable and well located, the owners super sweet and caring - The hosts are a very nice and caring couple. They were very welcoming from the beginning, helped us with information about the city and made everything possible to make us feel home. They also prepared an excellent homemade breakfast. The house is new, super clean, and very well furnished. A special place, very nice and comfortable and extremely well located to visit the city centre. Highly recommended.
• Ànnia (9/5): - Esmorzar molt abundant. Personal molt amable.
• Michele (10/5): Eccezionale - La stanza era bellissima, molto grande, molto pulita. Il bagno era anche molto grande. L'accoglienza è stata ottima, l'ospite è molto gentile e alla mattina mi è stata preparata una colazione molto buona. La posizione è comodissima al centro. Il wi-fi è veloce. Avrei voluto trascorrerci più tempo. Nulla
• stefania (10/5): - Eccellente sia nella posizione che nei proprietari. Struttura nuova e molto pulita Che non ho potuto starci di più
• B (10/5): - Heerlijke kamer en badkamer in nieuw hotel. Dagelijks een wisselend uitstekend ontbijt. De eigenaar en z'n vrouw zijn heel vriendelijk en behulpzaam ook voor bijzondere verzoeken. Het centrum is om de hoek. Ik kom graag terug.
• ManuelaArmida (10/5): - Ottimo hotel economico. Camera pulita spaziosa letto comodo frigorifero aria condizionata phon. Bagno nuovo. Negli spazi comuni un salotto e una cucina a disposizione frigorifero con dispenser per l'acqua. Colazione buona dolce e salata. Ottima posizione a breve distanza dalla piazza principale
• Foschi (10/5): - Hotel a conduzione familiare ampio, pulito e molto confortevole, in posizione centralissima. Camere molto spaziose, letti ampi e comodi. Un'accoglienza calorosa e un'ottima colazione!
• Lyudmila (10/5): - It was a very pleasant place, everything was good, we enjoyed our stay, they served a delicious breakfast, the host was friendly.
• Peter (10/5): - Perfect hosts. We enjoyed our stay in this modern clean and nice hotel. Great breakfast as well Nothing
• Felix (10/5): - Sehr netter Gastgeber, der gutes Englisch gesprochen hat. Das Frühstück war sehr vielfältig, schön und frisch angerichtet und für uns wurde sogar extra etwas Vegetarisches gekocht. Sehr sauber und praktische, zentrumsnahe Lage, von der aus man alles bequem zu Fuß erreichen kann.
• Natalia (10/5): Hovo (spelling?) and his wife clearly take great pride in what they do and are genuinely lovely people. Clean, great loc -
• Paul (10/5): Exceptional - Super friendly and helpful host. Comfortable room. Quiet location, just a short walk from the main square. Delicious breakfast Nothing
• Armen (10/5): Exceptional - Spacious, clean room with comfy beds. Very good breakfast. The entrance was from backyard
• Alexander (10/5): Exceptional - A Wonderful Stay at Hotel Sesil in Gyumri I recently stayed at Hotel Sesil in Gyumri, and it was an amazing experience from start to finish. The facility was modern, clean, and very comfortable. My room was spotless, full of natural light, and equipped with everything I needed. The staff was welcoming and attentive, always ready to help with any request. One of the highlights of my stay was the breakfast—especially their special omelet, which was absolutely delicious and a perfect start to the day. I would highly recommend Hotel Sesil to anyone visiting Gyumri. It's a perfect combination of comfort, hospitality, and great taste!
• Jun (10/5): Exceptional - Great breakfast. The omelet was so nice. Nice staff. Nothing. Note that the entire city wakes up late, and the earliest breakfast in the hotel is 8:30AM, though the staff can be flexible of the time.
• David (9/5): Superb -
• George (9/5): A good but somewhat pricey choice in Gyumri. - The couple that runs the place is very nice and helpful. The hotel is clean, the shower was pleasant and worked well in terms of water pressure and keeping a constant temperature, something I learned is rare in Armenia. Location is great, one block from the main square and walking distance to most things you would want to visit around the center of Gyumri. Wifi wasn't bad but it also wasn't great. I wouldn't want to depend on it if I had important video calls with multiple participants. For Armenia, especially outside of Yerevan, it's pretty expensive for a midrange accommodation. The room door does not block noise AT ALL; you can hear everything in the hallway and common area very clearly in the room. It's a small hotel, so all rooms are fairly close to that common space.
• Albert (10/5): Exceptional -
• Elizabeth (10/5): Exceptional - This hotel was great. Clean, modern, and run by a family that goes above and beyond to make their guests happy. One of the people we were traveling with was originally booked in a different hotel, but ended up spending the night due to issues in their hotel. At Sesil they let her stay with us and even provided her a complimentary breakfast alongside ours. They also helped us with our taxi to leave when we ran into issues and provided a special plant-based breakfast for me.
• Oana (10/5): Exceptional - The host was very kind, room was large and clean and breakfast was incredible. The best breakfast we had in Armenia! Everything was perfect
• Matthias (10/5): Next time again. - For all who don’t expect a luxury hotel (which wouldn’t be possible at this price), SESIL is a perfect choice. Clean rooms, all new. Bathroom top, hot water. Very good mattress, fine bed linen. Breakfast included and individually prepared and varying. Can be preordered earlier as usual in Gyumri. Hovhannes is always ready to help. He needs to install a small roof for not smoking in the rain ;-)
• Jason (9/5): Superb - Very clean, great location, host Hovo was great and made everything easy, breakfast was amazing
• Tatev (10/5): Exceptional - Highly Recommended! We had an absolutely wonderful experience from start to finish. The staff were incredibly welcoming, attentive, and professional, making sure every aspect of our stay was comfortable and enjoyable. Our room was very clean and well-appointed with everything we needed, including a very comfortable bed and modern amenities. The hotel’s location is perfect—close to major attractions, yet peaceful and quiet at night. We particularly enjoyed the breakfast, which offered a variety of home-made, fresh and delicious dishes. Our stay exceeded all our expectations. I would not hesitate to stay here again and highly recommend it to anyone looking for a high-quality hotel experience.
• Alike (10/5): Exceptional -
• Pavel (10/5): Exceptional -
• Michael (10/5): Memorable - The location is PERFECT… Nothing to be honest
• Farid (10/5): Simple clean place with a good night sleep and great breakfast in the heart of Gyumri - Great location and quiet property with clean rooms and comfy beds. The simple things in life. The place is nice with only a few rooms and a shared lounge dining area where you can chill and watch the world go by. Considering Gyumri is a small area I just wanted something affordable, well located and clean. The breakfast was fantastic, lots of choice, made right there in front of you fresh. The photos on Booking are a little messed up. But essentially you have 4-6 rooms, all with their own bathrooms. Nothing, everything was great. Be aware that there are steps needed to climb, but the host was very kind and offered to help in case you're unable to or not mobile enough. Wasn't a problem for me.
• Carlos (10/5): Exceptional -
• Sofia (10/5): Exceptional - Clean, new,very close to center.
• Karapetyan (10/5): Exceptional -
• Elena (10/5): 5 stars :) - Great place, very welcoming and caring hosts. It's spotless clean, comfy beds, central location and plentiful good breakfast in the morning. They even offered us a bigger room for free, which was very nice and warm, it's very important this time of the year ) Everything was just great :)
• Aavik (10/5): Exceptional - Great place to stay!
• Peter (8/5): Excellent inexpensive hotel with great breakfast - Just a short walk to the town centre, restaurants, churches and shops, the hotels entrance belies the very comfortable accommodation. The beds were comfy, the room very large, the bathroom sufficiently spacious with good towels, and the cooked and well presented choice of breakfast foods was excellent. A great one night stay. There was nothing to dislike.
• Aleksey (9/5): Small and nice hotel, very helpful and friendly staff. - Nice location, only 2 mins walk from the main square.
• Izabela (10/5): Best place to stay! - Everything was great: central location, ultra clean, comfortable and well equipped rooms, very friendly hosting couple, amazing breakfast we could not finish:D the best place we stayed in Armenia and even beyond
• Nozomi (10/5): Exceptional -
• Rina (10/5): Clean, great location, fantastic breakfast - Ideally located within a walking distance from major attractions, this small family-run hotel offers spotless clean rooms with Wifi. The breakfast is magnificent with an omelette, a selection of seasonal fruit and cheese. Try chechil, a local Gyumri specialty - this whey string cheese is both delicious and healthy.
• Astrid (10/5): Exceptional - The hosts were very nice and friendly. They gave us an upgrade to a bigger room for free. It was very clean and comfortable. Just 5 min. to the city centre.
• Begotxu (10/5): Perfect stay in Gyumri !! - The place is new and very cozy, The room and the bathroom were perfect. The bed was hug and very confortable. The breakfast was incredible !! We also had the opportunity to use the kitchen. It is very close to the main square. The couple that runs the hotel is very nice. If you are thinking of going to Gyumri, Sesil hotel is your place without doubt !! Armenian & Basque Country
• Rescmajster (10/5): Exceptional - The family hotel is a stone's away from the central plaza. It is very new and they are decorating more rooms... It is really spotless clean. The owner is very kind and the breakfast is prepared with care and love. It would be great if the bed linen can be changed to 100% cotton in future when they need to change it. Even with this small defect, the hotel deserve a 10.
• Armen (10/5): very accurate and clean rooms - tasty breakfast
• Balázs (9/5): Superb - There is a very modern, clean hotel near the city centre. It was dark a little bit.
• Suren (8/5): Very good -
• Riho (10/5): Exceptional -
• Tanja (10/5): Exceptional - Everything. The stuff is really friendly and actually speaks english so we were able to comunicate. The hotel is a 1-2min walk from the main square. There is a secured parking behind the building. The breakfast was actually one of the best we had. There is a kitchen that you can use and you can always have a coffee, the, so perfect for longer stays. Nothing. Hotel is even better than on the photos. 😁
• Peter (9/5): Great place to stay if you are in northern Armenia. Highly recommended. - Very nice hosts offering a warm welcome. Nice sized room with all the requirements provided. Excellent communal type breakfast with great fare. Street can be a little noisy early on in the evening. Parking on front or or behind building. Close to all necessary facilities in quite an interesting city. Nothing I can add here. The hotel had no shortcomings at all.
• Margaret (10/5): Fantastic hotel - Lovely modern & clean hotel. Quiet area of the city but an easy walk to the centre. The owners were great people and we really enjoyed our stay there. Nothing.
• Armen_ (10/5): Exceptional - Very friendly staff, the room we stayed was clean and comfortable too. Great location. Love the breakfast! It has everything we could expect to get from a hotel breakfast! Everything is ok
• Anna (10/5): Lovelyyy - It was exceptional indeed! Very comfortable, clean, location is great. People who run the place are super nice. Breakfast was homemade, lovely and delicious. Can only highly recommend!!
• Daniel (10/5): Exceptional - An absolutely fantastic stay which was met with some warm Armenian hospitality upon my arrival, offering me to sit down and enjoy some lunch as there was plenty there. The rooms are clean, modern and the beds are really comfortable. The breakfast is a superb spread and varied each day, by far the best I've had anywhere in a very long time. Hovo and his wife were very kind and welcoming and I'd encourage anyone staying in Gyumri to stay here. It's a great location too, only minutes away from the main square. The Internet was a little unstable at times, but generally usable.
• Karapetyan (10/5): Exceptional -
• Natalia (10/5): Exceptional - Nice cozy hotel in the centre of Gumry. Tasty breakfast and comfortable sleeping places.
• Hasmik (10/5): Exceptional - The stay was amazing, very hospitable staff, tasty breakfast, excellent location.
• Zarmik (10/5): Exceptional -
• Hetty (10/5): Stay with an extremely friendly and helpful host in a centrally located hotel - Very helpful and friendly owner. The location was fantastic. Breakfast was great. There is nothing we didn't like.
• Anoush (10/5): Exceptional - I was a returning guest, I stayed at the hotel ~1.5 years ago too. Cozy family-running hotel, with flexibility in check in and check out times, breakfast time, etc. The location is great! 2 minutes walk from the central square.
• Elina (10/5): Exceptional -
• Dmitrii (10/5): Exceptional -

Photos